I came across this free mind mapping, web based tool, called bubbl.us.
Mind mapping is a great way to visualize your thoughts, and work out the relationships between elements of a project or plan. This could be the delivery of a syllabus, if you're a teacher, or ideas for an essay, if you're a student.
I haven't had a chance to try it out in class yet, but I like the fact it's web based, can be embedded into blogs, and worked on collaboratively.
Bubbl.us is yet another example of how Web 2.0 technology is providing Software As A Service (or SAAS for short). I'm not sure how many of these companies will earn money, although the received wisdom currently seems to be that you offer the service for free, get in the user base, and then work out a way to charge for premium services. This model's called Freemium, but I'm not sure that we won't end up with another crash at some point.
For now, let's not worry about such matters - we're educators and students after all, and the breadth of the Web means that if one service shuts then another will doubtless spring up in its place.