Spotify API [finally!]

Today it happened, Spotify released an API. I’ve been waiting for this. Which apps we’ll be the first ones?

I’d like to code these two/three/four:

1. Auto-import new playlists to Facebook, dopplr-style.
2. Directly see which playlists your friends are creating.
3. See which songs your friends enjoy the most, or listen to the most in the last week.
4. Convert the Swedish Traxx-charts to a new weekly playlist.

What do you think? Which add-on services for Spotify do you need/want?