Swipebuster is using the private Tinder API to obtain Tinder user data. Swipebuster can find out if a specific person is using Tinder and can provide the most recent date that person used the Tinder app. Other companies that have had private APIs reverse engineered include Uber, SnapChat, and Tesla.
Google Buzz is a new service that takes aim at Facebook and Twitter by providing the ability to post links, photos and status updates directly from your Gmail account. And right off the bat Google has released the accompanying API.
With a domain like map.pr, you'd think this would be another link shortener. Instead, it uses the Foursquare API to give you a great way to visualize popular places on FourSquare. And, if you're following the World Cup, you can also use Mappr to find spots frequented by fellow fans.