Re: What's happening with bbPress?
BuddyPress is a series of plugins on top of WordPress MU… I don’t think that’s going to change. In fact, that sounds like the new plan for bbPress: to become a plugin on top of WordPress MU.
In terms of BuddyPress versus bbPress: BuddyPress actually uses bbPress code to power its forums. So using BuddyPress isn’t exactly walking away from bbPress… bbPress comes standard with a BuddyPress install!
In terms of what you use to power your sites, it’s probably best to choose your software solution based on your needs. If you want a social network with blogs thrown on top, BuddyPress is a good bet. If you want forum software with a plugin architecture, bbPress is currently the only game in town.