The word of the mouth is a very powerful thing and you can say something about someone that is not necessarily true, but people will believe it and it will become a constant reminder and every time that your name is bought up, that will come up.
In order for a service to be social, you've really got to start from the ground up. The fact that almost a third of the U.S. population have even heard of Spotify is really because they've seen it on Facebook and friends have been sharing.