Of all of the CMS platforms available today phpBB is perhaps the richest in functionality when it comes discussion forum software. It started as discussion forum software in 2000 and has not veered from that purpose in the slightest. As a matter of fact there have been many feable attempts at incorporating forums into many content management system platforms but still none come close to what a phpBB site can do as a forum.

phpBB is the easiest to set up and administer, and can be expanded and customized to suite your discussion forum needs. The drawback of phpBB however is that it's only function is as a discussion forum and cannot be easily expanded outside that realm. It can however installed and branded to match a similar look and feel of an existing website but as far as serving as a general purpose website - it will not.