I've found benefit using the Mind Mapping software, and I've found it to be a great communication tool when working with global colleagues and partners.

The challenge is that the same file structure is used to store the mind maps - <some folder> \ <some mind map>. After creating a few dozen mind maps, I find the brainstorming capabilities start to get bogged down in trying to keep track of the maps.

Has anyone found a tool that might address this challenge, keeping in my mind Sharepoint and other large collaboration tools are too expensive?

Any thoughts are appreciated.