I noticed this in the BP manual:
Please Note — The BuddyPress plugin only runs on one blog on your site which is normally your main blog.
And that seemed to imply only one blog can have BuddyPress installed. If I want, say, five blogs for five different communities, can each community live in one WPMU installation?
Alternatively, can we have five main blogs, and can all of them share one BuddyPress community?