1. A method, comprising: maintaining user-defined lists of content identifiers in a computer memory for corresponding user accounts, in response to user input defining collections of recorded audio and video works for respective ones of the user accounts; determining numeric scores each of which pertains to a different content identifier, the numeric scores comprising at least one of (a) popularity scores based on frequencies with which the ones of the content identifiers appear in the user-defined content lists or (b) relevancy scores each indicating a likelihood that content identified by one of the content identifiers will be of interest to a user; and providing image data and associated ones of the numeric scores to each of the client devices to enable display of distinct images each corresponding to a different content identifier in a matrix of images, the matrix representing contents of corresponding ones of the user-defined lists on the client devices wherein display size of each image in the matrix is determined at least in part by an associated one of the numeric scores determined for each content identifier.