KDE is mainly known for producing the KDE Desktop Environment (used in Kubuntu) for Linux.
Hugely popular Mozilla community providing support for Firefox, Thunderbird, Seamonkey and other well known Mozilla products. Over 350k members and 4 Million posts.
Professional online broker and trading community.
Active community for UK based Audi TT owners. Almost 30k members and 2 million posts, complete with unique style & powered by phpBB.
Fujitsu is a hardware and IT services company focused on providing IT-driven business solutions. Their community forum is powered by phpBB.
It is the Italian Community for Ubuntu, a popular open source community operating system based upon the the Debian Linux Distribution.