The long awaited Airbnb API is officially here. While Airbnb has publicly announced its official API, the API is not completely open to the public. Those interested must apply from access. Public documentation is not currently available. The focus of the initial API launch is the supply side.
Flight price tracker Yapta's value proposition sounds a bit like Robin Hood of the travel industry. It will not only track travel prices for you, but to help you get a refund should the price of your reservation fall after you’ve booked it. I wouldn’t be surprised if Yapta can also be used to retrieve kittens from high branches, but that part of the Yapta API isn’t documented yet.