1. A method of determining a numerical value of similarity as between a pair of artists, the method comprising: calculating for each artist a list of artist style values, each artist style value being representative of a style of the artist and a weight of such style as exhibited by such artist; calculating a set of style similarity values, each style similarity value setting forth a relative similarity as between two styles; and calculating, based on the list of artist style values for each artist and the calculated set of style similarity values, a style list comparison similarity score representing a relative similarity of the styles of the pair of artists.