I’ve just started using MindMeister; a free online mindmapping solution. Mindmeister lets you create up to 6 mindmaps absolutely free. You can share the mindmaps or keep them totally private.
You can share any of the maps by making them either ‘public’ (everyone can see them) or you can ‘invite’ people to collaborate with you and edit the maps. This makes this online application very powerful. The application also allows you to add task information (priorities, resources, dates) and icons to branches on your mindmap. You can also add url links, formatted text and attachments.
Overall mindmeister is a very useful GTD (getting things done) tool and great at collaborating/brainstorming with friends. Multiple people can edit the map at the same time; the application shows all changes to the map over time with a very easy to use slider date control.
I have created several maps; some I share with friends and some are public. “Top things that are interesting” is a map I created recently; I use it as a repository for articles I find on the web where the title says something like: “Top 10 things xxxxx”. This map is easy to share, you can see it here.
The applications sharing abilities allow you add a password so that people have to enter a password to view the map. You can also ’embed’ the map into your web page or blog – again that code to do this is included under properties for the map.