As the official board for the world-famous band Queen, this community hosts a wide variety of discussions by Queen fans from around the globe.
Avant Browser is a fast and user friendly browser which uses Microsoft's Trident rendering engine. The browser has been downloaded over 22 million times.
OpenOffice.org offers a free and fully-featured office suite which meets the needs of the common consumer all the way up to large enterprises.
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.
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.
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.