Friends and playlist revisions!

I posted on your blog but I guess this is the right forum for ideas...

I’d love a super simple “friends” list in the sidebar so you can just drag-n-drop songs to friends and they appear as ‘recommendations from friends’ or something similar. Also, automatically add invitees as friends and add people by email address or nick.
Connected to the friends thingy above. To be able to see who has added which songs to a collaborative playlist and see deleted songs in some kind of history pane would be awesome. Like Wikipedia revisions, I could only imagine what crap Wikipedia would be without that feature...

I'm sure you have a strategy for feature rollout too, and releasing to many at once would undermine users ability to comprehend the full potential of Spotify, but what if you add some kind of "labs" features like gmail has. So the users who really wan't the features can activate them, but they are hidden from casual users until they are ready for a full rollout.