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I know this has been asked a lot and I've explored the other answers, but I still have questions, so hopefully this sheds fresh insight on the debate.
A year ago I built a service scheduling web app from scratch in CodeIngniter with the following functionalities:
user management with different roles and functionalities
different backends for each user
interactive and manageable calendar for scheduling services
territory management and assignment
management for service status
reports and records
billing with authorize.net
front-end informational pages
All pretty standard stuff and codeIgniter worked great. Now, a year later, I'm revising the code. The client wants some different management features, like a CMS for the pages and to add new services and change the calculation price points, etc. I need to add new classes and code to make this work.
Over the last year I have dove very deep into Wordpress and realize that I could have built this whole app in wordpress using custom post types, taxonomies, custom fields, and expanded custom functionality though a custom plugin. In many ways, this seems like it would be better.
Pros of using Wordpress instead of php framework:
existing base with CMS, user management, familiar backend, database structure to start from, saving lots of development time
constantly updated security
stability
robustness (I know wordpress can handle this even though its intended use is for blogs)
Reasons to use a framework:
flexibility
ORM
MVC
other?
So... which is better? Do I really need ORM or MVC for this project? I feel my development efforts and client ux would be easier if I use Wordpress.
What else do I lose if I switch to wordpress?
What about combining Wordpress in a framework, or vice versa? Recommendations?
When does it make sense to use a framework instead of wordpress?
It's a fairly broad question, so here's a fairly broad answer...
Wordpress is a CMS. It's a good, flexible CMS with lots of built-in goodness, but its sweet spot is managing a site that's primarily about content, where content is very broadly defined as "words, pictures and other assets". The plug-in model lets you build/use additional functionality, and the wide user community provides lots of stability/security/scalability help.
Code Igniter is a framework that's designed for functional web apps (in practice, this usually means database-driven apps). Its sweet spot is managing complex interactions with a business domain. It is a framework for building any kind of app (including, if you were glutton for punishment, a CMS).
If your business domain is about content (and I don't think it is, based on your description), Wordpress is an obvious winner. In your case, I think you could probably build the solution using Wordpress, but it would be a real edge case - and the benefits you mention of "security, stability, robustness" would likely not apply, because you would need to build a lot of custom code. I think you'd very quickly get to the "well, it's not the way Wordpress wants me to work, but to deliver this feature, I just have to do it this way" point.
When business users say they want a CMS, they usually don't mean they want Wordpress (or Drupal, or Sitecore, or Magnolia); they want to be able to manage their site without having to go to the techies. If your site is primarily database-driven, that means screens to manage database records.
It's about structure and function in my view. Both CMS(Wordpress) and PHP Framework provide structure/functions to build your own functions. You can do the same things on CMS and Framework. They shouldn't have much difference on performance and security amongst well known Frameworks and CMSs.
However, CMS focus on Front-end (contents?), provides with ready to use CSS, Javascript (Front-end) in order to build / manage websites and web based applications easy and quick. Though, it's not very clear in structure comparing to MVC model.
Both would do the same job if you develop yourself, but in a team, framework could provide benefit.
It's only my view, I am using Wordpress a lot and a little knowledge on framework.
I use CodeIgniter and my bias is for that because you've already built the bulk of your app in it and because it seems more flexible/less pre-configured than Wordpress. I also get the feeling that CI is growing in use relative to WP with developers so CI seems possibly more future-proof, though to be fair they are both popular.
Can you make clearer you're bosses demands? The way I read what you say is that you're 80% of the way there and then are considering scraping (or at least possibly having to heavily revise) that 80% because the other 20% seem more logically done in Wordpress.
As I learn PHP more, I'm actually finding myself using even less of CI and writing more straight up PHP or actually JavaScript (for even better UX). So I guess I'm surprised to hear of someone wanting to switch from a minimal PHP/ruby/Python framework to a heavier one since most of the work is shifting to JavaScript these days.
Another key point on going towards straight-up PHP is that the number of people who know PHP dwarfs the number of people who are familiar with CI- or WP-specific syntax. So you are more likely to get help/collaborations/career advancement focusing on a solid foundation in the "mother tongue" over these minority dialects. Doing this with PHP is also having the benefit of helping me understand other languages such as JavaScript better since the level of abstraction is on the same page with php-ruby-python, whereas a framework brings in an entirely different (an in my increasing view, extraneous) vocabulary.
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I am in the process of architecting an application. It will be a large, enterprise class web application. Thousands of users could upload files, search large number of blog entries with chat functionality and such. It will also have mobile interface. It should be highly testable, scalable and flexible.
I have narrowed it down to three environments: pure play ASP.NET, pure play DotNetNuke (DNN) and a combination of ASP.NET and DNN. To keep this very brief, here are some 'for' and 'against' on each of the options:
ASP.NET:
for: highly scalable, supports patterns like MVC, testable, consistent architecture.
against: long development time.
DotNetNuke:
for: short development time, large number of existing functional modules and skins.
against: architecture is sealed, can't support MVC, unit testing is difficult, inconsistent modules/skins, potential upgrade issues, user experience is inconsistent due to disparate modules from different vendors, poor documentation.
So, the questions are: what do you think? Has anyone switched from DNN to ASP.NET (and, vice versa)? Have you objectively evaluated these two and what did you choose?
Highly appreciate your help. Thanks.
henry.
DNN is ASP.NET, just with a lot of the work done for you.
Also, please remember that just because raw ASP.NET has the potential to be more scalable, doesn't mean that you are actually going to built it to be more scalable. Or that you will built it well in the first place.
It comes down to a trade off between control and resouces/talent. If you have many very talented developers (like, top-10% talent), a lot of time, clearly defined requirements for your site, and consumers who will be patient while you build out the infrastruture, by all means go with raw ASP.NET.
However, if you need to build it quickly and need to be flexible, or you have limited development resources, you might have to sacrifice some of that control and unit testing and potential performance (again, the "potential" part is key here).
Based on what you are looking for, I'd recommend you go with a platform like DNN, or a million other ones line SiteFinity or Umbraco or Orchard or something like that (some of them like Umbraco give you MVC too). It gives you a lot of the infrastructure and plumbing common among a lot of sites, probably done better than you are going to do it, so that you can focus your resources on the truly unique aspects of your application.
Just stay away from SharePoint. It's evil.
I've built raw ASP.NET sites for really customized applications, which was good because I didn't need a lot of plumbing and wanted really unique funcitonality through the site. But then I've built social networking sites with DNN, which worked well because it had packaged components for blogs and forums and chat and all that stuff, plus allowed for easy skinning. I designed another application for a customer that they wanted to have a lot of custom functionality, but they also wanted to updated a lot of content and internatalized it, so we used a Umbraco for that. And right now I have a ASP.NET app that works great, but I want to add in some social features, so I'm going plug in a Umbraco or DNN site that integrates with it to host the more common social components.
I would definitely recommend DNN based on your very limited list of needed features. You can always build a custom module to meet your exact needs or modify an existing open source module as needed. You can use the MVP approach in your module development to improve the testability.
Have you considered the Umbraco CMS? It is built on .Net (v5 is MVC3). It is open source and a very robust and well supported application. It has been used for the asp.net site for example.
It has a very short development time, many modules, extremely flexible and I find it very easy to extend. For example, I rolled my own workflow, event driven publishing and have created multiple custom administration sections for managing bespoke functionality external to Umbraco.
You can use XSLT, Usercontrols or Razor to create template modules.
It has a fantastic community too.
Should I avoid using a CMS if I want to be able to quickly make good sites with more features/options to customize than Wordpress?
I want to become a better webdeveloper and able to quickly make good, fast, secure websites with lots of functionality without being limited so as I'd be with Wordpress. I don't see writing lots of plug-ins to reach the same functionality as a nice solution for doing my own programming.
I have written a few games, quizzes and other scripts I'd like to be able to recycle or easily adapt to work with the CMS.
I currently have a multi-lingual website that works with a /nl/ and /en/ part, that has a few self-written games I wrote in PHP.
CakePHP has a very good CMS called Croogo. It's still quite a young project (still in beta and being actively developed), but the great thing about it is that its a Cake app so it's coded to the well-documented Cake standards.
Whereas customizing/extending Wordpress, Joomla, Drupal et al would mean you'd have to invest a huge amount of time learning about their respective frameworks, all for the sake of one part of any given website (the CMS), if you learn CakePHP, you're learning a much more advanced and flexible framework that can pretty much be used to do anything well beyond the confines of CMSes.
If you learn Cake (or if you already know Cake) you'll find that you already understand Croogo without having to invest much additional time at all. Code you write in Cake can easily be packaged to be a Croogo plugin and even if Croogo doesn't stay around for the long term (I hope it will!), it wouldn't be difficult to re-factor all the plugins you've written to work in any other Cake-based CMS that comes along in the future, or even your own Cake apps.
Croogo is pretty basic, but quite powerful. It has a Wordpress-like feel to it, it supports nice URLs via an amazing reverse-routing system, the /en/ /nl/ language thing you mentioned works out of the box and it's very easy to get any of the huge array of Cake components and plugins working in harmony with the CMS through the use of hooks.
I'm currently working on a project using joomla and there are a ton of custom features that I need to implement. I usually have to create a plugin or module in that case. It's a pain. I'd much prefer doing most of this from scratch instead of hacking at the code. If I had a choice, I would not use a CMS. I hate them.
I think ultimately it's about long term support. When you build a custom CMS in cake or another framework it is much easier and faster for you to customize and build the way you wan too. This works great if this is a project you are planning on supporting (by this I mean bug/user support for when you unleash this CMS on non devs). This can become a headache pretty fast when things need updates and clients are looking for fixes and changes. It's completely manageable, just more of a headache then something with community support.
That being said, if you are comfortable in wordpress the amount of support that exists in that community is huge. So often times you can leave the project knowing updates for the CMS and plugins will come in at a regular speed.
TLDR So if it's a project you know you will be supporting long term (or people with the same comfort and skill level as you) then I would say build it your self for ease of build and customization. If this is a one off or something you plan on handing off to a client with little to no support, building inside of a community supported platform is best.
I really comes down to priorities, if you what to build a site really fast a CSM is hard to beat, but you do not have the same control over the core as you do when you wright it from scratch.
But you can do most any thing with plugins/modules so the control is there if you are willing to work for it. If you wright it your self you will be the only set of eyes most of the time so it will in most cases be slower to implement new standers and security fix's (because you will need to find them first) but with a CMS you will have many people working to make it better and safe at the same time.
If you want to be well rounded I think youe need to be able to do both, you can't control what the customer wants to use some times.
You can make site very quickly with a CMS like Joomla but the problem is even having over 7000 extensions sometimes for your particular purpose you don't find an extension and developing an extension can be real tough. it requires a comprehensive knowledge of Framework. If all you need to do is manage content CMS is the best choice. If it is like a web app and require more interactions go for some framework which provide the basic skeleton of your app. e.g. for CRUD operation many frameworks provide scaffolding feature and make this thing a piece of cake. CakePHP, CodeIgniter, Kohana are some of the best PHP frameworks you can use.
Using Chinese Cms DedeCms or phpcms And developer it more easily !
I like PHPCMS, it works with nginx, fasctcgi, mysql on linux or windows.
I use it to make portal site or enterprise sites group. The multi-site architecture and PHPSSO works well. Template engine is also strong enough.
take a look at big mysite: xinm123.com
Most important thing: it's open source.
I need to develop a newspaper site in Drupal, I've already played around with Drupal a little, and I think I know which modules would best suit my purposes. Naturally, one of the modules I'll be needing to use most is Views, but I have a couple of questions:
Because this is a content-intensive site, I was wondering if using 5-6 views on each page to generate node teaser + thumbnail lists would impact performance adversely?
I am a designer with significant front-end development experience. Like I said I've played around with Drupal quite a bit and other than running into a few hurdles which I eventually overcame, for the most part I was able to get it to do what I needed it to. Having said that, does one also need strong programming skills to fully develop a site in Drupal?
Thank you very much for your help!
Jane
Views offers caching and Drupal also has block caching, which should help you improve performance. The SQL that Views generates is never as good as handwritten SQL, but if you make simple Views, the SQL is actually quite good and not a performance problem (unless you have millions of page views).
If you can create the features you need, with modules from Drupal.org, you don't need strong developer skills. But you do need to know some PHP to make a Drupal theme which is what controls the layout of the site. It will also be a great help, in understanding the Drupal theming system, but not a requirement.
First off, check out openpublishapp.com for a Drupal distro that is made for publishers from the ground up, it's pretty hot.
To answer your questions:
1) As far as performance and views goes, having 5-6 views on a page is a normal requirement for a drupal news site and the performance issues are usually handled by views/panel cache, and using a page cache like Varnish in front of a web server, Object caches like Memcached (for the DB) and opcode caches like APC...if you don't want to learn all that off the bat you should still be fine if your traffic isn't too intense (but go sign up at getpantheon.com for awesome hosting with all of that and the kitchen sink, and check out groups.drupal.org/pantheon)
2) If the functionality exists by way of core/contrib modules, to fully develop a site for the most part one only needs to understand enough PHP to theme, and often with starter themes like Fusion, and some of the others you hardly even need that, just an understanding of how they work and are extended (which is well documented). That said, if you want functionality that doesn't exist, you'll have to code it, or have someone code it for which strong programming skills are desired, but not necessarily required :)
Even I recommend the use of the OPENPUBLISH - https://www.acquia.com/solutions/publishing
On top of to this you can make an efficient usage of
1. APC - PHP byte-code caching
2. Drupal Caching - block/template/view level caching
3. Boost - Caching module which doesn’t need any external tools
4. Varnish - HTTP accelerator
5. Memcache - Data intensive content.
Apart from this you will also need to think effectively on deciding on DEPLOYMENT ARCHITECTURE of the site - preferably Acquia or Amazon environment.
Learning curve may vary depending on your current skills in PHP or Drupal. Usage of already established distribution like OPENPUBLISH may help you to minimize the dependability on too much custom coding.
I've started to wondering whether ASP.NET Webforms/MVC even have a place in the web developers toolbox anymore... It seems that CMS systems like Umbraco have replaced the web developers job. Yes I know that those CMS systems are built with ASP.NET Webforms/MVC - however is there even any reason for learning those things if all you gonna do is to use a CMS system anyway? - Also I cant find any situation where a CMS system can be replaced by your own web application.
My question is therefore: Is there any reason for learning Webforms/MVC when using a CMS?
EDIT:
My question might be more like: When should I use a CMS, and when should I go and build my own web app?
The problem with CMS solutions, and I mean all CMS solutions (not just Umbraco, or other .NET solutions, but in any language) is that you will always pay a price for using them. You may gain more from the time-savings afforded by using the CMS, but there are trade-offs to consider:
You will sacrifice a great deal of flexibility
You could pay a significant performance penalty. Many CMSs load a large amount of modules and code to service every request, and much of this is not relevant to a particular page function. (though some CMSs are more monstrously heavy than others!)
The future of your project is tied to yet another vendor, and their own choices
Very often, you rule out the possibility of using other databases that might have better fit your customer's needs (Umbraco doesn't support PostgreSQL, Kentico only supports SQL Server)
Once you start using a CMS you will be tied into satisfying the architectural decisions and API of the CMS framework, and you could eventually be backed into a corner.
This can be particularly problematic if your 'site' is more of a web application than a pure content delivery site. In such cases it can make more sense to choose to build using the full flexibility of the web application framework, rather than risk getting backed into an architectural corner.
On the other hand, if you are building a web site that has potentially hundreds of pages, with a lot of user-contributed content and is much less of a web application, then often a CMS is the way to go, and makes a lot of sense. But remember, you now have two frameworks and two APIs to learn and manage (your platform's framework and the CMS framework).
Writing a CMS is like invading Afghanistan.
Everybody gets a turn but nobody wins.
I don't think that Stack Overflow could have been built with a CMS. Does that answer your question? =)
Update
To answer your updated question.
If you want a regular corporation web containing news, articles, forum etc: Go ahead and use a CMS.
If you need to build a more custom web site like stackoverflow, a web interface for a system or anything like that: Built it using MVC etc.
I personally use a CMS for our corparate website and a MVC framework to build user and administration interfaces for our products.
Not every problem needs a CMS. In the same way not every problem needs a bespoke MVC/webforms website. It depends on what your requirements are. You pick the technology to solve the problem.
Build vs buy is the hardest decision to make. As a developer build always looks best. You can do better than that pile of carp they want to buy. Nevermind that you're reinventing the wheel, axel, cart, etc. To users/management buy always looks best. They don't have to think to hard about what they want and can have it now, not 3 months later after you write it. They forget it'll cost the same again to customise & make it impossible to upgrade.
I'll stop ranting now.
Umbraco is a pretty bare minimum CMS. To customize it (e.g. Version 7+) you'll need to know Heavy MVC, JSON, XML, Sql, etc.
In fact a Site built on Umbraco 7+ is entirely based on MVC views you set yourself and assign to SurfaceControllers (which are MVC controllers) and all you are really getting is the ability for users to edit things about your pages and have Umbraco manage it for you in a DB.
In short you still need experienced web developers to build a site on Umbraco, they just save a lot of time by not having to build the entire backend from scratch.
You use Umbraco to organize Document Types that define what Templates (MVC Views) are used for rendering different types of documetns (e.g. Web Pages) and then you built the template from the ground up with 100% control over the HTML, Css, and Javascript that get's output.
Imo Umbraco is more of a Framework like Django than a complete CMS.
Sure you can build a site in Umbraco and not customize anything, but it would be a pretty cheesey site.
The whole point to Umbraco is to give skilled .Net Developers a good platform for building a site on top of it, but they still have to build it.
Now sharepoint would be more of a complete CMS out of the box that you can do a lot with, but let's see a few problems with SharePoint...
Resource Heavy, eats 50+ Gig's to install
Eats 16 GB of ram just to boot it up (Sharepoint 2013)
Requires Sql Server 2008 R2 or equivalent (enterprise license, $$ chaching)
Requires Windows Server ($$chaching)
It's a monster basically, if all you need is a user editable blod platform... man what a waste of money. Foundation is free, but doesn't include things like the Blog Site Template, so you buy a server enterprise license ($$ big cachinge, 40,000$+ in some scenarios...)
Agreed. A CMS like Umbraco provides a (very) good out-of-the-box solution for the most basic applications. Any sort of specialized purpose is going to require additional programming knowledge. Anymore, though, and your major, if not primary need is going to be a good understanding of the business need. I think we're getting away from building the Legos themselves and on to building the neat toys with the Legos. Cheers!
A CMS (or similar application framework) will provide you with a lot of functionality out of the box, and many of them also have a good library of plug-ins. But you'll still need to write WebForms/MVC code if you want to add any custom features.
We want to build a web application, that is specific to our domain, but also includes forums, blogs, etc in this application. Some integration points to Twitter and Facebook are also required.
There will also be a desktop application that connects to our web application for uploading data and downloading configuration and reports.
The question is, can we extend Drupal to host both the regular modules and our web application? (There will be business entities and their properties and daily data uploaded from the desktop application)
Or can Drupal be integrated with external applications? As an example, users and roles need to be the same and consistent across both. We may also want data from the web application searchable in Drupal.
I know this is a bit vague, but I cannot reveal more. I am very new to content management and I just wanted to know if someone has built this kind of application.
I try to rephrase what you wrote, just for you to check that I got your question right. You basically need to create a web application that:
Implements some of the standard functionality of Drupal
Have some custom functionality that should "blend into" the Drupal one (same users, same permissions, etc...)
Be able to upload/download content (or data) from desktop applications.
If I got you right, the short answer is: yes, you can do that with Drupal.
Now for the extensive one:
- Drupal has literally thousands of modules, so I expect you to get most of the things you want by simply installing the right combination of readily available modules.
- Of course, any custom functionality can easily be implemented in form of a module too (quite standard thing these days).
- The interaction with a desktop application is normally implemented via webservices rather than querying the DB directly. Drupal comes natively with a xmlrpc server and client, but you can scale up to SOAP - if you wish - via a couple of contrib modules.
Some additional thoughts:
If you choose to use Drupal, and you start from scratch, then you have to be aware you and your team will need to dedicate some time and effort to understand how Drupal works. Although - differently than Palantir - I stuck with Drupal, I agree with her/him on the fact that Drupal gets complicated complex right off the bat. This is the trade-off you have to pay in order to have a platform that - rest assured - is very flexible, extremely pluggable and rock-solid (otherwise it wouldn't have been used to redesign the whitehouse, nor Drupal would have got for the second year in a row the "best PHP CMS" award, I suppose).
The good news is: there are some excellent books out there, and I would certainly recommend "Pro Drupal Development" for an in-depth and all-around explanation of the system. Just be sure to get the 2nd edition, as the first deals with the now obsolete 5 seres. That said...
A very good thing about Drupal, at least in my opinion, is that most of the tweaks you might need to do to an existing functionality can be implemented by hooking into the original code from a custom module too. This IMO is the biggest advantage of Drupal: you never have to touch other developers' code to achieve your goals, and this means - for example - that you will be able to keep your core and contrib modules up-to-date without breaking any customisation you might have done.
Drupal is heavy. Compared to other CMS it sucks plenty of processing power and RAM from your server, and - unless you are going to have a very small site - I recommend to deploy it in conjunction with nginx, rather than Apache.
Drupal scales well, thanks to a good mechanism of caching and "throttling up" mechanisms. Strange as it might sound, Drupal scales very well on large traffic websites, so that big increases in traffic do not necessarily imply big increases in resource usage.
The user experience out-of-the-box on a Drupal site is quite poor. There is a massive work being done on this at the moment (here and here (video)), but improvements won't be available until D7 is released [soon, but then you will have to wait for the modules to be ported], so it is advisable to allocate some time to create an administrative theme, if the admins of your website won't be of the technical type.
At the end of the day, my advice is: if your site is going to go big / complex / with complicated business logic and lots of functionality, then Drupal is probably a good candidate. If your site is contrarily a small-scale one with standard functionality plus a few custom bits, maybe Wordpress / Joomla could fit your needs better [not because they are 'less powerful' but because Drupal strengths would be unused in this case, while Wordpress/Joomla simpler architecture would probably represent an advantage in this scenario]
Other options would certainly be frameworks like CakePHP or Django, for example, but that - IMO - is a totally different approach to the matter, I would say.
Short answer: Drupal is well suited to build something like that, especially if you are willing to integrate your app/logic into Drupal as a suite of custom modules. The other way, integrating Drupal into an external application, can also be done, but will give you more friction, as Drupals architecture is pretty much geared towards being a framework in its own right.
Longer answer: I have a pretty much opposite opinion/experience compared to Palantirs. I've been working almost exclusively with Drupal for a year now, in the context of two fairly complex/'enterprisy' projects (after several years of 'on the side' usage for smaller things). While I agree that it imposes some rigid rules (but not limits!), I consider this to be an advantage, as those rules give a clear guidance and provide proven ways on how to do things. The three parts Palantir mentions are good examples for this:
Menu system - Provides a well structured and effective dispatching mechanism that is easy to extend with your own stuff, while giving huge flexibility to tweak/manipulate existing/default paths. (Note that 'menu system' in Drupal denotes the whole topic of managing your URL space, not just the subset of 'visible' menus that is usually associated with the term)
Forms API - A declarative approach to web forms, with a well designed processing workflow and a whole lot of built in security features that you would otherwise have to take care of yourself. Also highly extensible, with straight options to adjust/extend already existing forms on demand, add new validation rules to any field or whole forms, multi step forms, javascript based form adjustments, etc.
Translation system - This is pretty complex, simply because internationalization is fricking hard to do. But it is built in, again giving clear guidance on how to do things in order to work in a generic way (though there are problems with quite some contributed modules that are not using/supporting it the way they should).
I could give more examples for parts where I appreciate the 'rules', but this post is getting long already, and I still have to cover some downsides ;)
So to sum up the positive part - if I where given the rough specs you posted, I'd say 'no problem' and go with Drupal, being confident that it would be a solid foundation for the custom parts, while providing all the 'standards' like forum, blogs, twitter/facebook integration and many, many others in the form of already existing solutions (even though those might need some adaption/tweaking).
Downsides: As always, there are flaws, and some of them are substantial, depending on requirements/circumstances.
Learning curve - Drupal is quite complex, and 'grokking' its concepts takes time. 'Playing with it for a week', as Palantir suggests, will certainly give you a general feeling/broad impression, but it is in no way enough to allow for a serious judgement of its pros and cons, as those will only surface while coding in/for it. So if you are already deeply familiar with an established web development framework, this might be an issue. If you have to learn one anyways, this should be less of a problem.
Database restrictions - As of Drupal 6, database support is MySQL or PostgreSQL only, using a Drupal specific 'abstraction layer' (which obviously isn't one ;)
Drupal 7 will move to PDO, which should (finally) end this questionable state.
Test/Stage/Production migrations - Parts of Drupals 'out of the box' flexibility are due to many things being configurable in the administrative backend, which implies that many important configuration settings are stored in the database. This makes migration of data and/or configuration between several instances pretty difficult/tedious, once you left the (early) stages of development where you can get away with complete dump/restore operations (see e.g. this question & answers)
These are the main ones for me, but you'll probably find more :)
I worked for over a year using drupal extensively, but I ended up abandoning it. Drupal, and other CMS systems out there, have very rigid limits and rules. I'd use Drupal for projects where you have simple requirements and few or no business rules. Drupal gets complicated almost immediately when you want to do complex things (especially pay attention at the menu system, forms, and the translation system if you need to be multilingual).
If your system will really be large, with all the things you mentioned, then I'd rather use a PHP framework to implement your business logic, and integrate external products as they fit (a forum, a blog, a twitter client, etc...).
But the advice is: don't trust anyone :) Download it, and play with it for a week. You'll be able to make your mind and be more confident about your choice!
As Drupal is open source, you can pretty much do as you wish with it. A couple of points though:
Changing Drupal's user/role structure would be tedious and unnecessary. You would need to have your desktop application authenticate from Drupal's MySQL database.
Drupal has hundreds of plugins for just about everything, so Drupal could no doubt run the whole "web" side of things including visitor stats etc. You would just need, again, to connect your desktop application to the correct MySQL tables and show the data as desired.
Don't forget to check other content management systems such as Joomla! (and many others). Each has its pros and cons. www.opensourcecms.com allows you to easily test CMSs and I've used it extensively in the past.
Just be sure to map out all the components first. Every hour planning up front saves many hours of headaches later.