1. A method comprising: with a microphone of a portable device, receiving audio from a user's ambient environment over a prolonged interval of at least fifteen minutes; applying an algorithm to data representing the received audio to derive identification data therefrom; by reference to the derived identification data, determining at least first and second different items of audio content to which the user was exposed during said interval; by reference to said determined first and second different items of audio content, priming software for later use by the user, said priming comprising receiving first and second items of auxiliary content at the portable device from one or more remote repositories, the first item of auxiliary content being associated with the first determined item of audio content, and the second item of auxiliary content being associated with the second determined item of audio content; presenting to the user a listing that identifies the determined first and second items of audio content; and in response to a user selection of one of said determined items of audio content as being of interest, taking action in accordance with the primed software, using a corresponding item of auxiliary content; wherein items of audio content to which the user is exposed are monitored, and associated auxiliary content is received by the portable device in advance of the user selecting a particular item of audio content as being of interest.