I'm on a paid Spotify subscription for almost a year now. And every day - and I mean every single day - when I'm opening the desktop app, in the Discovery section, among other random recommendations, there is a message that one of my friends is listening to John Legend.
Every day since February 2013...
Now I know for a fact that my friend doesn't give a *&^% about John Legend, he listened to his music once, maybe twice on Spotify. But that's it.
So I'm suspecting that maybe the record company or whatever, has paid to push those messages across the Spotify network. There is no other explanation for this. This or for the fact, that when you open a new spotify account, your default radio station is Rihanna and you can't change/delete it.
Now here's an example: there are two big companies competing in TV/movie streaming subscriptions. One offers all content with no ads, the other has adds that you can't skip. I've subscribed to the company that has no ads. I had all information I need to make a choice between the two.
So I want Spotify to be completely transparent and honest about what content is in fact advertising.