Disqus.com is a very good online self hosted discussion and debate platform. It is a social web2.0 application it can be integrated in every website be it static or dynamic or CMS based web site like Joomla, Wordpress and Drupal etc.
Recently disqus.com has updated its backend application and added some social feature like now one can comment and discuss thing via social accounts although it has its core account setup option.
The client site version of demo you can see the below of this post. This post comment section is being managed by disqus.com so if you want to leave your comment you can leave in below comment form via through your social accounts like facebook and twitter OR you can simply sign up disqus with the Name and email id.
It is quite easy and simple.
Beautiful, real-time, engaging discussions for your website.
With a few quick steps, you can turn your old comment system into a new way to engage your visitors.From small blogs to massive websites, Disqus is the easiest way to build active communities. It's free to use and works with virtually any type of website.