DISQUS - Disqus is a global comment system that improves discussion on websites and connects conversations across the web.
Quuu - Quuu is a curated content suggestion platform that connects to your Buffer queue, allowing you to grow a relevant social media following across your entire social landscape.
Commento - A fast, bloat-free comments system to foster discussion on your website
Written - Written helps content marketers build their audience by licensing content and audience from bloggers.
utterances - A lightweight comments widget built on GitHub issues.
Taboola - Drive traffic to your site, blog or video, or monetize your site with the largest platform for content recommendation, audience acquisition, and native advertising.