Developer Tools - Pligg
Pligg - is a Web 2.0 Content Management System (CMS) unlike any other existing CMS. The user interface gives your visitors a reason to come back to your site by making them decide on the site's content and giving them the chance to build a social network. The Pligg community has grown to over 10,000 registered users sharing and trading tips, more than 60,000 Sourceforge downloads and 2 IRC rooms that are active 24/7 selling everything from custom templates and modules, to support and installation.