In this paper we present how sharing and utilizing mind maps could enhance search applications such as document search engines and recommender systems. In addition, we briefly present the first research results which indicate that mind maps can be used to determine document relatedness and therefore can enhance document recommender systems. We also discuss some challenges that information retrieval on mind maps will probably have to overcome. Categories and Subject Descriptors H.3.3 [Information Storage and Retrieval]: Information Search and Retrieval