How much would a stranger know about you if they knew only the last song you listened to? Quite a bit, at least according to the stranger. Music taste often acts as proxy for our personalities, and we constantly perform this taste perception online. In our study, we find that good first impressions are common, bad first impressions are extreme, and that people pick up on many subtle cues about personality and whether they share common values based on data found in an online music profile. Similar motivations for listening to music and the perception of individuality are more highly valued than similar taste in genres or artists, suggesting that social media applications could benefit from incorporating these motivations in predicting compatibility between users.