DISQUS - Disqus is a global comment system that improves discussion on websites and connects conversations across the web.
Mobilize - Mobilize is a scalable messaging app built for large groups.
Commento - A fast, bloat-free comments system to foster discussion on your website
NationBuilder - The world's first platform for leaders, handcrafted from scratch to help you grow your community and lead them to action.
SolidOpinion - SolidOpinion is a fun, new and dynamic commenting platform.
FUEL CYCLE by Passenger - Think Passenger builds online platforms that allow brands to connect, create and communicate with key stakeholders.