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.
Pixelmator is a popular commercial image editing software for Mac OS X users.
Adblock Plus is one of the most popular Firefox Add-ons in the world, with over 10 Million daily users and over 100k downloads a day. They use phpBB to offer support to their users.
Zend Technologies is one of the largest and most popular companies producing a wide variety of tools and frameworks for PHP. Their community forums rely on phpBB.
Official Support Forum for Debian, the kernel-based open source operating system. phpBB provides a solid platform for support and discussion.