Sometimes known as mind-mapping, this is a more creative way of recording information or developing ideas. It can be particularly useful for brainstorming, i.e. getting lots of initial ideas down quickly without detail. It is also useful for developing ideas for an assignment before you have a clear idea of how the flow of the assignment should be or which points are more important than others.
See the example below which shows possible notes developed for an assignment concerning the consequences of the number of vehicles on the roads: