1. A method for generating concept structures from signature reduced clusters (SRCs), comprising: retrieving from a storage at least one SRC including a cluster of signatures respective of a plurality of multimedia data elements (MMDEs); generating metadata for the cluster of signatures included in the at least one retrieved SRC; associating the generated metadata with the at least one retrieved SRC; matching the at least one retrieved SRC with a plurality of previously generated SRCs stored in the storage, wherein each of the plurality of previously generated SRCs that matches the at least one retrieved SRC forms a concept structure, wherein the concept structure includes at least metadata associated with the SRC matching the at least one retrieved SRC.