It is the Italian Community for Ubuntu, a popular open source community operating system based upon the the Debian Linux Distribution.
Support for Synology NAS devices and ideas for future versions of the DiskStation software.
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.
Active community for UK based Audi TT owners. Almost 30k members and 2 million posts, complete with unique style & powered by phpBB.
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.
OpenCart is popular, powerful, and easy to use shopping cart software. Their healthy community forums are powered by phpBB.