Event ticketing service SeatGeek has made its internal recommendations service available in the SeatGeek API. Developers can now integrate the advanced recommendations functionality of the SeatGeek platform into websites and applications.
Gowalla, Foursquare, Yelp, Facebook Places, the list goes on. There's certainly no shortage of methods to tell people where you are and what you're doing while you're there. Startup Whatser, built on the SoGeo API for location-based apps, has jumped into the ring with a different approach to check-in services: to be useful.