The Raspberry Pi is a cheap, credit-card sized computer. The official website uses phpBB for their discussion forums.
Fujitsu is a hardware and IT services company focused on providing IT-driven business solutions. Their community forum is powered by phpBB.
Conquer Club is an online multiplayer world domination game. The discussion forum is host to over 500,000 members and 2.8 million posts.
OpenCart is popular, powerful, and easy to use shopping cart software. Their healthy community forums are 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.