From an artist's perspective, the decision to sign up for Spotify basically comes down to one question:<p>Does the benefit in music discovery make up for the cost of losing album/download sales?<p>I did the calculations once and I forget the details, but the gist is that without factoring in music discovery benefit, an indie artist probably only hopes someone chooses to stream instead of download if the listener is going to stream the song around 1,000 times or more. Otherwise, you get more financial upside if they buy the download.<p>So the question is if any discovery benefit will shrink that number enough. This would include the people who stream and don't buy but would never have bought in the first place, as well as the people who stream and then buy.<p>The answer is difficult to prove because you get into weird counterfactual questions, and there really aren't any good studies out there from unbiased experimenters. But it's pretty reasonable for a rational musician to decide that any discovery benefit will not make up for the cost in losing album or download sales.