1) The document describes a technique called Listener Anonymizer that aims to camouflage users' music play logs to preserve their demographic anonymity from being predicted. 2) Listener Anonymizer works by computing the effectiveness of different songs at anonymizing a user's nationality, gender, or age based on their play log, and recommending songs to play that will anonymize their demographics. 3) By playing the recommended songs, it biases the prediction of a user's demographics from their play log, preserving their anonymity while still allowing them to use music recommendation services.