Epoch - 100% realtime chat and commenting in a tiny little package that is fully CDN and cache compatible.
TechGasp Comments Master is the professional integration of facebook comments into heavy duty wordpress websites.
The WP Social Comments lets people comment on content (pages, posts etc) on your site using their Facebook account.
AJAX comment system. Insert and displays Comments easily and quickly using Ajax style of social networks.
This plugin will help you display Facebook Comments on your website. You can use it on your pages/posts.
WordPress Comments Import Export plugin is a fast way for export and import WordPress Comments.
Integrate Facebook Comments, Vkontakte Comments and/or Disqus Comments along with default comment form at your WordPress website