BuddyPress - WordPress social networking in a box.
Ultimate Member - The easiest way to create powerful online communities and beautiful user profiles with WordPress.
Elgg - Opensource social network engine
Paid Memberships Pro - The complete membership solution for your WordPress site.
SocialEngine - Socialengine PHP: Elevating Your Online Community Experience.
WP-Members - WP-Members is a free membership management framework for WordPress that restricts content to...