Both seem to have a free version with some limitations, and subscription versions with the limits removed.
Mindomo “free” limits you to seven private maps and includes ads, Mindomo Premium (not yet available) allows multiple users to collaborate on the same map, unlimited private maps, and a secure, faster server … for 5 Euros/month. There are also business and education packs.
- Here is a trivial mind map in Mindomo … [update: link removed: map didn’t show up, even though the title looked right]
MindMeister is currently in private beta (I have invitations if you’re interested) – while in private beta, testers have access to all functionality, which includes simultaneous collaboration, the imports and unlimited maps. Post-beta, the free (ad-supported version) will be limited to 5 maps and sharing of maps (i.e. not simultaneous); and the premium version is 3.21Euros/month. It wasn’t clear to me if this was confined to the premium version, but there is Skype integration so you can start a conversation online while collaborating.
- Here’s the innovation mind map from a long time ago, imported from Freemind into MindMeister … [update: link removed: you need to log in to see it!!]
After the brief look, I prefer MindMeister, but that might just be my “open” bias against Flash, and because it imports Freemind maps (Freemind is open-source) … but maybe not. The Mindmeister site seemed a little more informative, and you can get their news as an RSS feed.