xkcd
Discussion board for the massively popular xkcd web comic. Covering everything from Maths and Science to Logic Puzzles and Forum Games. Over 100k members and 2.4 Million posts.
Bokt.nl
Independent site for Dutch horse lovers. With over 280,000 members and 95 million posts, Bokt.nl is widely acclaimed as one of the largest boards powered by phpBB.
Raspberry Pi
The Raspberry Pi is a cheap, credit-card sized computer. The official website uses phpBB for their discussion forums.
NationStates
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.
Sky Italy
Italy's home to the multi-national media giant, Sky. Sky's range of enterprises include digital television, broadband, phone lines, news broadcasting and sport broadcasting.
Waze
Waze is the world's largest community-based traffic and navigation app. Join other drivers in your area who share real-time traffic and road info, saving everyone time and gas money on their daily commute.