1. A method for generating concept structures from signature reduced clusters (SRCs), comprising: retrieving at least one SRC including a cluster of signatures respective of a plurality of multimedia data elements (MMDEs); generating at least one metadata for each signature of the cluster of signatures; identifying a number of repetitions of a metadata of the at least one generated metadata; and determining whether the number of repetitions of the metadata exceeds a predefined repetition threshold; upon determining that the number of repetitions of the metadata exceeds the predefined repetition threshold, identifying the metadata as representative of the SRC; comparing the representative metadata to metadata that is representative of at least one previously generated SRC to determine a metadata match; and upon determining the metadata match, identifying the retrieved SRC and the matching previously generated SRC as a concept structure.