BuddyPress.org

I am using it here at: http://duvar.fenerbook.com

I had to get rid of the “blog authors” link from the adminbar, because of too many authors and also page loading was slow.

I have the wordpress video plugin (enabled site wide) which works well with p2 theme and member blogs as well!

http://www.daburna.de/blog/2006/12/13/wordpress-video-plugin

Hope it helps.