Forum-style, collaborative mind maps.
Visual root is a place to create online, collaborative mind-maps using video, images, and text.
Practically, the goal is for one person to start with an idea, or topic, and for other people to be able expand and improvise on that idea using different forms of media.
You could also view the site as an image-board of sorts, where there's an initial post or thread, and image and video (and text) responses to that thread and the entire thread has a mind-map like structure.
A very interesting application which produces irregular mind maps from one "root" that can be an idea, a concept, an image etc.
The maps are created by the users, they are interactive and "live", you can move the nodes around, interact with other people, vote on individual nodes, zoom in and out, share portions of maps.
Great for collaborative school projects and presentations.