32. The computer-implemented method of claim 30 , wherein the audio document is or includes at least one of (A) a radio program, (B) a live or recorded musical work with lyrics, (C) a live or recorded dramatic work with dialog or a monolog, (D) a live or recorded talk show, (E) a voice mail, and (F′) a segment of an audio conversation.
30. A computer-implemented method comprising: a) accepting, with an advertising system including at least one computer, relevance information for an audio document; b) determining, with the advertising system, a plurality of advertisements relevant to the audio document using the relevance information and serving constraints of the advertisements; c) selecting, with the advertising system, at least one of the determined relevant advertisements to be served with the audio document; d) transmitting, with the advertising system, the audio document for delivery to an end user client device; and e) transmitting, with the advertising system, the selected at least one of the determined relevant advertisements for delivery to the end user client device, wherein the act of selecting occurs after the act of transmitting the audio document has been completed and a play operation has been initiated on the audio document.