DISQUS - Disqus is a global comment system that improves discussion on websites and connects conversations across the web.
Zoom - Equip your team with tools designed to collaborate, connect, and engage with teammates and customers, no matter where you’re located, all in one platform.
IntenseDebate - IntenseDebate's comment system enhances and encourages conversation on your blog or website.
Discourse - Discourse is an open source discussion platform built for the next decade of the Internet.
Whereby (formerly appear.in) - Collaborate from anywhere - video meetings with no downloads
Viafoura - Viafoura is an easy-to-integrate social monetization platform that enables your to better engage, understand and monetize your community.