phpBB is the holy grail of free and open source forum/discussion board on the internet. With tons of plugins, themes and a amazing community, its probably the best too. But for those like me who don’t want the bloat, and would rather use a simple and easy to manage forum, here are a few alternatives:
SimpleMachines - Probably the second best known free forum script. Slimmer than phpBB, and with a better, cleaner admin interface, its my personal favourie. And yes, it does have its fair share of themes/plugins and good community support.
FluxBB - This one is “really” light. The download comes in under 300kb, is XTML and CSS valid, and with a minimal but delightful interface is bound to loved by Mac fans.
bbPress - Comes from the creators of Wordpress, its their in house forum software. Nuff said.
Vanilla - Other than having a tasty name, it also offers a very small and simple forum. Great for “minimal” fans.
Phorum - Its an open source PHP forum. Probably not as good looking as the others, but does the job well.