I write as a hobby, and I'm already finding this sleek little app very useful to keep tabs on plot elements, characters and progress, although I think it would probably be useful for many other things.

Some suggestions for use: meal planning (make a matrix of your weekly shoppling list to know what you have to work with) to school work (memorize the cast of King Lear with familial connections, map out the animal kingdom, connect metaphors for a term paper) to business (plan a timeline for that big leap public) to collectors to hobbyists to -- well, a lot of things.

Despite a learning curve, MyMind is definitely worth a try.