DISQUS - Disqus is a global comment system that improves discussion on websites and connects conversations across the web.
Hive - Seamless project management and collaboration for your team.
Master Comments System - Master Comments System is a very compact comments system with basic options:
Sup! Standup Bot - The complete stand-up and follow-up bot
talkatv - talkatv is an open source comment service much like ...
Asana - Asana project management is an effort to re-imagine how we work together, through modern productivity software. Fast and versatile, Asana helps individuals and groups get more done.