Hello Andy, excellent job, I love wordpress…. I have been testing all community and multiuser blog systems and while Buddypress is still in a marvel work on development I prefer to wait for BP instead of installing and developing on any other platform… WordPress MU+Buddypress rock and will drive the social communites in not time….
I am testing buddypress at http://www.aula5.net, aula5 will be an educational+young people community in the Dominican Republic, the only thing I am missing is the Album feature, this is the main reason for people to enter in any community, PICTURES, PHOTOS.