Let's you map out all the ideas for your game on a tree, and export it to cool formats. A great tool for organizing ideas. I use it for trying to think of every possible feature to be implemented into my game, the levels, the setup of a level, the menu, etc. Once the mind map is complete and very detailed, it gives a really good solid foundation to start coding with. It also is a good tool to show how complex a seemingly "simple" idea is, and the feasibility of such an idea.
If you can't mind map it, you can't code it.
I'd suppose this would work well for any large software projects.