Less than a month ago, Google made all public activities available via its "firehose." Last week, the search giant updated the Buzz API again with several interesting features, including a limited firehose, which is calls a "garden hose."
Magnify.net, a web service that allows individuals and companies to build and curate their own video channels and communities, has announced an API to enable developers to pull videos and data from their Magnify.net channels and integrate them into their own applications (details at our Magnify.net API Profile).
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.