The Signature Quadratic Form Distance is an adaptive similarity measure for flexible content-based feature representations of multimedia data. In this paper, we present a deep survey of the mathematical foundation of this similarity measure which encompasses the classic Quadratic Form Distance defined only for the comparison between two feature histograms of the same length and structure. Moreover, we give the benefits of the Signature Quadratic Form Distance and experimental evaluation on numerous real-world databases. Categories and Subject Descriptors H.3.3 [Information Search and Retrieval]: Retrieval Models General Terms Theory, Experimentation, Performance Keywords Signature Quadratic Form Distance, Content-Based Similarity, Feature Signatures, Multimedia Information Retrieval