Exploratree is a free web resource where you can access a library of ready-made interactive thinking guides, print them, edit them or make your own. You can share them and work on them in groups too.
Mind mapping is the best way to understand and visualize something. You don't even have to explain it to someone else - explaining things to yourself is a powerful way to learn and understand.
Text 2 Mind Map is a web application that converts texts to mind maps.
It takes a structured list of words or sentences, interprets it,
and draws a mind map out of them
The IHMC CmapTools program empowers users to construct, navigate, share and criticize knowledge models represented as concept maps. It allows users to, among many other features, construct their Cmaps in their personal computer, share them on servers (CmapServers) anywhere on the Internet, link their Cmaps to other Cmaps on servers, automatically create web pages of their concept maps on servers, edit their maps synchronously (at the same time) with other users on the Internet, and search the web for information relevant to a concept map.