Tech Crunch has details on Check.in

"Eventually, the plan is to release a native app version for the different platforms, but in order to get it out there relatively quickly, they made a web version that works on mobile browser that offer HTML5 support for location (currently the iPhone and Android phones). When you load it up, the browser asks for permission to pull your coordinates, and a few seconds later it pulls up a list of venues it believes you’re near. When you click on one, the app does some “magical matching” to find the venue across the various services."







