[ricardojr]

The only thing I could think of is that Rdio or any ad-network is sharing information with a 3rd party and that 3rd party pushing the info to Spotify. The other way is through your social network like activity. Did you "like" the band on Rdio?

[Aaronn]

Rdio has public listening history built in: http://www.rdio.com/people/[INSERT USERNAME]/history/

[mendozao]

Why would rdio make this information public? It seems like really valuable information that they are just freely allowing to get scraped

[mendozao]

ah ha! this has to be it..

[mendozao]

I didn't "like" the band, I just listened to their stuff normally. Since Spotify runs natively, I wonder if they have a way to access browser information

[ricardojr]

I say spend some time trying to re-create it. Maybe some activity within Spotify itself triggered the email.