Hugely popular Mozilla community providing support for Firefox, Thunderbird, Seamonkey and other well known Mozilla products. Over 350k members and 4 Million posts.
Fujitsu is a hardware and IT services company focused on providing IT-driven business solutions. Their community forum is powered by phpBB.
Info-Mac is a community dating back to 1984 as a mailing list and was the first online community for Apple's Macintosh computer. All of their content was converted to phpBB in 2007.
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.
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.
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.