1. A method of generating a playlist of affinity related media files comprising: receiving, by at least one processing unit, from a user belonging to a population of users in a media service, a selected media file attribute of a plurality of media file attributes, each of said plurality of attributes associated with a media file and having one of a plurality of attribute types comprising at least album, artist, title and genre related to said media file, wherein receiving said selected media file attribute represents said user's desire to create an affinity playlist of media files having an affinity relationship based upon said selected media file attribute; accessing, by the at least one processing unit, affinity relationship data for generating affinity relationships among media file attributes, said affinity relationships comprising affinity relationships among same and different media file attribute types, said affinity relationship data being based upon said population of users' ratings associated with media file attributes, an affinity relationship among first and second media file attributes being generated using a number of users of said population whose rating score associated with the first media file attribute is equal to or greater than a predetermined rating score threshold and a number of users of said population whose rating score associated with the second media file attribute is equal to or greater than the predetermined rating score threshold; and assembling, by the at least one processing unit, a playlist of media file identifiers using said affinity relationships among the media file attributes, including the affinity relationships among attributes of different attribute types, said playlist comprising a media file identifier associated with a playlist media file selected for said playlist by virtue of having a media file attribute that has an affinity relationship with said selected media file attribute but that is not said selected media file attribute.