I came across LikeBids and they say they are launching today. It seems like they get vendors to provide users a chance to win products on their sites just by telling their friends about them. "LikeBids has replaced currency with social media collateral with “likes” and “tweets”."

Read more here: LikeBids launches today, offers chance to win items by tweeting and liking | AuctioneerTech
Video: YouTube - LikeBids.com - Get Friends, Get Likes, Get Stuff!

If you'd like to become a vendor, you can contact them at:

AIM:LikeBids
Skype:LikeBids
Email:Eric@likebids.com