Today I was searching for a free mind mapping tool that I could use on my MacOS and ideally one that I could use on Windows as well and sync between the two. In my searching, I came across this gem. It is 100% web based, and free. I was very skeptical of how good it could be given its pricetag as well as the fact that it was completely web-based, however after using it, I am very impressed. The tool is called wisemapping, and the following is a screenshot:
If you are into mind mapping, you really need to give this one a try!