Kialo - Kialo is the platform for rational debate. Empowering reason through friendly and open discussions.
DebateIsland - DebateIsland.com is a leading online debate platform which uses A.I. to revolutionize online debating. The site features numerous debating formats including Casual, "Persuade Me," Formalish, Formal Traditional Debating, and Lincoln-Douglas Debating.
DebateGraph - Graph visualization of: Join a global community of mappers with over half a million ideas and 30,000 maps. Click on the bubbles to explore, and log-in to create free public & private maps on any topic!
DebateArt.com - DebateArt is a unique and growing community committed to the idea of exchanging views and perspectives through debating.
Rationale - Rationale let's you create, online, argument maps.
OmniDebate - A crowdsourcing and debate platform for climate change activists.