If you know anything about Joomla, you know the awesomeness is in the extensions. The templates and template design, content and sections and categories are the core of your site, yes, and decide much of the functionality but installed components, modules and mambots make replicating hundreds of hours of programming take literally minutes, sometimes under a minute. Things like adding a forum take me literraly less than 60 seconds. Same with comments to articles. Anyway... here are a few key components : BloggX : BloggX is just plain amazing. What does it do? It allows you to edit the content of your site from a program. This means adding a new article, or editting existing articles is as simple as clicking a button. It makes updating your Joomla! site take seconds instead of minutes. It saves you ALOL of hassle and alot of time... also the joomla interface is a little laggy sometimes, so this removes that. It's both an external application AND a mambot. FireBoard 1.0.0 : New release... it's sleek, it looks great and installs right out of the box. Great forum, super easy... what more is there to say. Community Builder : Bit of a learning curve on this one I hear, have not used it but know what it can do... turn your site from a website to a community. Change user regitration, force whatever fields you want, etc. etc. lots of stuff oriented around getting people back to your sites. On the joomla! page there are litterally hundreds of extensions, for things like PAYMENT SYSTEMS, VIDEO STREAMING... everything you can imagine.
http://extensions.joomla.org/component/option,com_mtree/task,listfeatured/cat_id,0/Itemid,35/ this is of course the joomla website, not my own, it's an 'editors choice' pick of extensions... on the left menu has all 3rd party extensions... hundreds upon hundreds OF EXTENSIONS, the vast majority of which are absolutely free for commercial use.