1. A computer-implemented method comprising: (a) maintaining, by a computer system including at least one computer, a database comprising: (1) first electronic data related to identification of one or more reference electronic works; and (2) second electronic data related to action information comprising an action to perform corresponding to each of the one or more reference electronic works; (b) obtaining, by the computer system, extracted features of a first electronic work; (c) identifying, by the computer system, the first electronic work by comparing the extracted features of the first electronic work with the first electronic data in the database using a non-exhaustive neighbor search; (d) determining, by the computer system, the action information corresponding to the identified first electronic work based on the second electronic data in the database; and (e) associating, by the computer system, the determined action information with the identified first electronic work.