Disqus for WordPress now has Full Single Sign-On (SSO) Support taking advantage of both WordPress’ and Disqus’ login systems by allowing sites to set their own custom login button, making the login process incredibly seamless for both existing and new visitors.
Disqus, pronounced “discuss”, is a service and tool for web comments and discussions. Disqus makes commenting easier and more interactive, while connecting websites and commenters across a thriving discussion community.
The Disqus for WordPress plugin seamlessly integrates using the Disqus API and by syncing with WordPress comments.
Disqus for WordPress
Uses the Disqus API
Comments indexable by search engines (SEO-friendly)
Support for importing existing comments
Auto-sync (backup) of comments with Disqus and WordPress database
Threaded comments and replies
Notifications and reply by email
Subscribe and RSS options
Aggregated comments and social mentions
Powerful moderation and admin tools
Full spam filtering, blacklists and whitelists
Support for Disqus community widgets
Connected with a large discussion community
Increased exposure and readership
Plugin homepage: http://disqus.com/