OpenCart is popular, powerful, and easy to use shopping cart software. Their healthy community forums are powered by phpBB.
KDE is mainly known for producing the KDE Desktop Environment (used in Kubuntu) for Linux.
Professional online broker and trading community.
OpenOffice.org offers a free and fully-featured office suite which meets the needs of the common consumer all the way up to large enterprises.
The Raspberry Pi is a cheap, credit-card sized computer. The official website uses phpBB for their discussion forums.
Discussion forum for the massively popular American animated sitcom. Powered by phpBB.