The free ad-supported streaming only works for the first six months, it seems. AFAIK, Spotify does that virtually forever, with the limit of a certain hours of streaming per month. I think I like the spotify method better, since I never really hit that limit but will want to keep using it for free after six months.
Still, it's looking good. And amazingly, it's apparently going to be available outside of the US, Canada, and the UK.