DebateGraph is described as 'gives you a way to create, explore, and understand individual maps of thought, dialogue, and debate – and the graph of interconnected maps – through a set of complementary and cognitively enhancing visualizations'. There are four alternatives to DebateGraph, not only websites but also apps for Self-Hosted solutions, Windows, Linux and Mac. The best alternative is argunet editor, which is both free and Open Source. Other great sites and apps similar to DebateGraph are Arguman (Free, Open Source), Cohere (Free) and Rationale (Paid).
Argunet Editor is a free argument map editor for analyzing and visualizing complex debates. You can use it offline and save your debates on your hard-disk. Or you can use it as a client-server application.
Arguman.org is an open source, argument analysis platform where you can create and analyze arguments using logically constructed argument maps in a social environment. Construct your own arguments or add to and voice your support for arguments others construct.
The Web is about IDEAS+PEOPLE. Cohere is a visual tool to create, connect and share Ideas. Back them up with websites. Support or challenge them. Embed them to spread virally. Discover who - literally - connects with your thinking.