An online debate tool facilitates the act of debating by helping to manage the structure of argumentation. This distinguishes it from general purpose communication tools such as wikis and forums. Some online debate tools provide graphical representations of arguments, but this is not a requirement.

This wiki page and tag gives a list and characterization of debate tools. Debate tools were previously discussed here.

Literature

There exists an academic literature on argument mapping and other tools (computer aided or not) for assisting debate. The most recent survey seems to be "Computer-supported argumentation: A review of the state of the art" written in June 2009, which lists 50 tools (starting on page 94).

Online Deliberation is a related discipline that asks what are the effects of online discussions, when are they effective, and how to design better systems.

List of debate tools

Debate Map

Summary: Tree-based mapping of beliefs, arguments, and evidence.

first mentioned:
- a comment by Venryx
pros:
- Collaborative creation, editing, and evaluation of debate/argument maps.
- Open source. (under the MIT license)
- Developed using modern web technologies. (react-js, mobx, firestore)
- Ability to enter both formal arguments (premises and conclusion), or less structured "single-premise arguments".
- Rating system for the truth/probability of claims, as well as the relevance/validity of arguments.
- Tree-based structure which can extend very deep without loss of clarity or usability.
- Integrated term/definition system. Terms can be defined once, then used anywhere, with hover-based definition display.
cons:
- Has a learning curve for casual users, as content must conform to the argument<-premise structure at each level.
- Not yet made usable on mobile devices.

DebateArt

Summary: Debating platform with rich one-on-one debates functionality and advanced discussions forum.

pros:
- Clean and convenient design.
- Advanced and flexible one-on-one debating system.
- Separate forum for casual discussions.
- Private messaging system.
- Great performance.
- Friendly community.
- Active and thorough moderation.
cons:
- Has a learning curve for casual users.
- No dedicated mobile version.

debategraph.org

Summary: This... is pretty much exactly what we were looking for, isn't it? Though it doesn't do anything with probabilities.

first mentioned:
- a comment by Peer Infinity
pros:
- collaboratively edit argument maps
cons:
- it doesn't do anything

...