I saw a girls startup plan that involved exclusively using Facebook. I was like, "You really need to support Flickr, Twitter. You shouldn't depend on one source for your customers to pull photos." She said they were just going Facebook because it was the quickest route to get a deliverable product. She obviously wasn't an engineer and I'm sure any software dev will tell you if you support at least two services, you'll write code in such a way that's expandable to many (more modular, classes for each service type). Even if that 2nd service may not have any customer base, it's worth the implementation cost just to have.

This doesn't really relate to this story as Price Zombie did utilize many different sites, but it does show just how big the giants are (like Facebook/Amazon) that even if you try to support lots of different sources, one of them can make or break you.