From PostgreSQL wiki
FUDforum is a free and ultra fast discussion forum with top notch features like importing of XML feeds, mailing lists and USENET posts.
FUDforum currently supports PostgreSQL 8.1 or greater. Both PostgreSQL and PDO drivers are available.
Help is needed to test FUDforum against new PostgreSQL releases and suggest further optimizations.
It would also be great if someone can step up and implement tsearch2 support in FUDforum.