Mindmeister is an excellent online mind-mapping tool which allows users to brainstorm and organise plans and ideas.
Mindmeister provides users with the ability to create a mind map by dragging and dropping elements around the screen, adding and deleting new branches, while the finished maps can be shared with others. Very intuitive it is - nicely executed.
Launched earlier this year, Mindmeister is free to use, though it does have a number of subscription options. The paid-for packages unlock advanced features for subscribers, such as the ability to collaborate. Subs start from about $50 a year.
There is of course some competition. Bubbl.us is another, similar mind mapping tool which is completely free to use, though it lacks some of the premium features of Mindmeister, and the latter is slightly easier to pick up. Mashable has a list of around 30 other competitors.
Mindmeister, based in Germany, has also launched an offline version of the tool (still in beta) that allows you to create maps anywhere and update changes onto your account when you are back online.