It is the Italian Community for Ubuntu, a popular open source community operating system based upon the the Debian Linux Distribution.
Professional online broker and trading community.
OpenCart is popular, powerful, and easy to use shopping cart software. Their healthy community forums are powered by phpBB.
Discussion forum for the massively popular American animated sitcom. Powered by phpBB.
Gentoo Linux is an open source operating system built on top of the Linux kernel and based on the Portage package management system.
Discussion board for the massively popular xkcd web comic. Covering everything from Maths and Science to Logic Puzzles and Forum Games. Over 100k members and 2.4 Million posts.