OpenCart is popular, powerful, and easy to use shopping cart software. Their healthy community forums are powered by phpBB.
The Raspberry Pi is a cheap, credit-card sized computer. The official website uses phpBB for their discussion forums.
Joomla is one of the leading open-source Content Management Systems. With a userbase of over 400,000, they use phpBB as a reliable platform for support.
Meristation Magazine is a Spanish-language website featuring articles on gaming. Their discussion forums hold over 34 million posts and are powered by phpBB.
GameServers is a premier Game Hosting company, having collaborations with big names such as Infinity Ward, Treyarch and Epic Studios.
Boasting almost 14 million posts, Ars Technica is one of the biggest and oldest technical forums still operating today. They use phpBB to power their forums and comment system.