PayPal to launch a new, social, group-buying tool called Shoptimist
Details are thin, but it looks like Shoptimist will be a Groupon with emphasis on real-world, physical products. Fellow shoppers will band together to get cheaper deals from suppliers -- and the more people that join in, the better the deal. That's where the social aspect comes in: you'll want to add friends to your 'purchasing group' so that you can open up the cheapest prices. No doubt, all of your recent purchases will be fed through to your Facebook wall, too.
There also seems to be a 'sweepstakes' element to Shoptimist -- like this Facebook page for a chance to win! -- but I suspect that's just to drum up initial interest in the service.