They probably just observered listening habits. I'd fire up Spotify, listen to it for a day or two, then hit the limit (that I always seem to forget exists). And just switch it off for another month or so. Limits or adverts would suit me. I hate, hate, hate the ads, and soon tire of the free service. My laptop's sound is pretty horrid that it's not worth me buying the subscription, but Spotify is still useful as a sampler.