Mind maps can be used to learn grammar and vocabulary. They are also useful for organizing thoughts on a topic in the target language before engaging in a conversation or writing about a particular topic. Mind maps are maps of connections between ideas that a student creates on paper with various colors and images or they can be created digitally. Mind maps look like neurons and represent the schemata that is created in the brain as it attempts to connect concepts. It is a refection of how memory is created. 
Each person draws a mind map in a different way. Some are clean and orderly, while others seem to be pure chaos. Mind mapping is meant to represent individual thinking patterns. Students can use colors, pictures or whatever they want to make their mind map understandable and useful to them.
Here is an in-depth article on how mind maps can be used effectively in foreign language learning.
Thanks for the post. I recently began to make mind maps to help me learn Chinese. I also want to blog about my experience with it. Your article is helpful and explains the crux of mind maps in a way that is easy to understand.