1. A method comprising: receiving, in a portable audio device, audio data representing samples of audio content, for rendering into human-perceptible sound; applying a digital watermark decoding or audio fingerprinting algorithm to the received audio data to derive identification data therefrom; by reference to the derived identification data, selecting a particular software program for use-with-said-audio-content rendering of said audio data into said human-perceptible sound, said selecting being performed by a processor in the portable audio device that is configured to perform such act; and launching said selected software program; wherein selection of the particular software program that renders the audio data is based on identification data derived from the audio data.