ParticipateDB

IntenseDebate is a blog commenting system that supports Typepad, Blogger and Wordpress blogs. The system allows blog owners to track and moderate comments from one place with features like threading, comment analytics, user profiles and reputation, reply-by-email, comment voting, and comment aggregation. Users can comment using Facebook, Twitter, Gravatar, a site-created online identity, and guest account. Administrators have moderation and blacklisting powers, spam filters (using "Akismet"https://akismet.com/), and can assign multiple users as admins. IntenseDebate is developed by Automattic headquartered in San Francisco, California (US) with a worldwide staff.