[Developer]

High-Level Evaluation

There are several resources that can help you to get a high-level view of the overall capabilities of Joomla!.
Web Sites Running Joomla!

One way to evaluate a CMS package is to look at web sites that run on it. It is impossible to say how many web sites run Joomla!, but we do know that over 5 million copies of the software have been downloaded since March 2007.
Joomla! has a forum called Site Showcase that allows you to look at a number of sites running on Joomla!. Obviously, these represent a tiny fraction of the total number of Joomla!-run sites worldwide. A simple demonstration site is available for viewing. This site contains a lot of useful information about Joomla! features and the Joomla! community.
If you are evaluating Joomla! for a school, university, or non-profit organization, you might want to look at the Non-Profit Site Showcase or the Schools and Universities forum.
And, of course, don't forget to include all of the Joomla.org sites as examples of what can be done with Joomla!, since they of course are all run on our favourite CMS package.
Extensions

An important feature of Joomla! is the ability for third-party developers to easily extend Joomla!'s core functionality with "Extensions". Extensions in Joomla! are third-party software programs that can be installed along with Joomla! to provide additional functionality. Joomla! is designed to be extended in this way, and, once installed, these extensions look and work just as if they were part of the core program.
One of the strengths of Joomla! is the large and active developer community creating extensions. There are over 3,000 extensions currently available, with more being added daily. Many are open source, like Joomla!. Others are offered as commercial software. To get an idea of the variety of extensions available, visit the Joomla! Extensions site.
Community

The developer community is one part of a larger Joomla! community. For example, there are over 200,000 active registered users on the various Joomla! forums, with over 150 new participants every day. These forums are very active, with over 1,200 posts per day, and provide a high level of free support to Joomla! users. To get an idea of the types of questions answered in the forums, visit the General Questions forum.
Support

An important question when evaluating any software package is the quality of support available. In addition to the support forums, Joomla! has a large community of skilled web professionals and consulting organizations who use Joomla! to create and maintain a wide variety of web sites. Take a look at the Professional Services forum to get a view of this community. There are also a growing number of local Joomla! user groups.