Spotify launched in the US today, to become the third serious provider after MOG and RDIO services that offer unlimited streaming of their catalog for a rather small-ish monthly fee. Napster, Real, ZunePass, Thumbplay (now sold away), also offer a similar service, but they never managed to capture the market the same way. I have used all three services above over the last year (some in a short trial mode, some through lengthy subscription), so here's how I see them go down.