I’m going through the past few years of ideas that are in my moleskine notebooks. Some of the ideas are really lacking, but might give you an idea? All of these ideas are yours for the taking. Don’t forget my archive of 100+ web startup ideas.
User would enable this app for their Facebook profile. They input their eBay username and it displays your auctions to friends and visitors of your profile. The app would have an affiliate account with eBay and earn that way.
It also seems like there should be a website where I connect Facebook and Twitter, and then see what auctions my friends are selling (and watching?).