BuddyPress.org

IMHO WPMU, BuddyPress and bbPress works well if:

– You set a wildcard domain (in my test site subdirectory based instalation doesn’t work)

– BbPress table is in the same database as BuddyPress, WPMU and i. ..

– BbPress has the same prefix as WPMU. For example, if you use a standard prefix to the WordPress table (for example wp_) then for bbPress give wp_bb_