Conquer Club is an online multiplayer world domination game. The discussion forum is host to over 500,000 members and 2.8 million posts.
Inspired by Max Berry's book, Jennifer Government, NationStates is one of the most popular online simulation games. The forum boasts over 5 million posts and 200,000 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.
Developed by Focus Home Interactive, Cities XL 2011 is a city simulation game. Their community forums are powered by 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.
VirtualBox, developed by Oracle, is cross-platform x86 virtualisation software. It has become one of the most widely used virtualisation solutions in the world.