There are over 50 (!) biomedical community sites in my constantly updated list. Here are the 2 newest additions.
bevalley is a global network where healthcare professionals and organizations share medical facts and the ways they use them. It includes several applications to work with data, such as analysis tools and graphical representations. bevalley is free of charge and grows in a controlled way through an invitation system. Each user has a limited number of exclusive invites to the network. If you already know some users in bevalley, ask them to invite you!
Vivu: a network of professionals and users that care about our health and wellness.