This blog is now using an interesting new comment system called DISQUS. I like Disqus for the following reasons:
1. It allows users to log in via multiple sites such as Twitter, Facebook, Open Id, Yahoo and Disqus itself
2. It allows users to track all their comments made across multiple sites, at a single place
3. When users manage their comments through Disqus and / or log into Disqus via one of their social networking accounts, the comment they make also gets published in their social networking feed resulting in greater propagation of the source post where the comment was made
4. Incredibly easy and smooth integration with wordpress