Does the world need another social network? (cough, no, but people are still going to make them).
Combine Amazon's wonderful ability to recommend products based on what you buy/rate - and the goal of every 2nd grader to collect stickers - and you get http://getglue.com
You create and account and then pick things you "like" (or "don't like" if you prefer) - and as you pick more things it's recommendations get better. As you comment/review and "check in" to items (such as checking into M Griffin listening to "Fabrications") - you can have your status updated automagically to twitter or facebook.
Silly? Yep - totally. Mindless timewaster which is probably why I've been enjoying it the last few weeks.
Why I like Get Glue... mainly for the "check in" ability - I can note what I'm listening to on an artists page - and then a couple weeks later when I check into that artist again I can see how many times I've listened to that album. Or watched that tv show, or played that video game, etc...
They claim they're a social network - but other than seeing what other people "like" - I don't really see any form of communication going on (unless I'm just skimming the surface...) - but I can't even "message" people I follow.
The other nice thing about this network is you can add stuff that's not there - via Amazon, Wikipedia, Discogs, Last.fm, and a ton of other places... So - if you're favorite artist who's only released on a tiny ambient label or netlabel isn't in there - you can add them.
I haven't seen Apple's Ping yet - but it sounds awefully similar for the music side - and doesnm't allow 'adds' lke getglue does.