1. A digital works identification system comprising: a first memory for storing information permitting identification of digital works of copyright owners including at least one content based fingerprint for each of the digital works, wherein each of the at least one content based fingerprint has a corresponding feature sequence; a digital input receiver for receiving at least one packet-based digital signal transmitted over a network; a second memory for storing at least one portion of the at least one packet-based digital signal; and at least one processor for identifying at least one of a file type of the at least one packet-based digital signal and a content of the at least one packet-based digital signal; obtaining at least one feature from the at least one digital signal, wherein each feature is a plurality of characteristics of the at least one packet-based digital signal at a point in time, generating a content-based fingerprint for the at least one packet-based digital signal from the at least one feature, wherein the content-based fingerprint of the at least one digital signal has a corresponding feature sequence, determining whether the at least one feature matches stored identifying information of a digital work of a copyright owner by performing an identification comparison between the feature sequence of the content-based fingerprint of the at least one packet-based digital signal and the feature sequence of a content-based fingerprint of one of the digital works of copyright owners to determine that a work represented by the at least one packet-based digital signal is a match to one of the digital works of copyright owners, and upon a successful determination of whether the at least one feature matches stored identifying information of a digital work of a copyright owner, performing at least one of sending a message to a destination address directing the destination address to a commercial site where authorization to obtain the content may be purchased, and disabling transmission of at least a portion of the at least one packet-based digital signal if the destination address is not authorized to receive the content of the at least one digital signal.