FourSquare

Oct'2010 - the FaceBook app on my Android Nexus One doesn't have a CheckIn feature...

Mar'2010: manually creating your own Event (tradeshow) as temporary Venue

May'2010: used by music venues (clubs, concert halls)

Oct2010 - StephanieMarcus on Event Planning with FourSquare, Facebook Events, Twitter, and other services.

http://foursquare.com/apps/
http://groups.google.com/group/foursquare-api
Five things you should know
Ruby gem http://github.com/jeremyrwelch/Foursquare
main document - method details
Mar'2013: Shoot a video in Vine, scribble a reminder in EverNote, make a post on PathCom, or snap a photo in Instagram, and you can place-tag it. When you do, you’ll see a little banner pop up that says “Powered by Foursquare.”... “When some new place opens up, our users go in and add it that same day. When a place closes down, we’ve got five people instantly reporting it as closed.”... The Venues API matches raw geodata with real place names like “Union Square” or “Sparky’s Diner.” Unlike the rest of Foursquare’s API, you don’t have to be an authenticated user to query Foursquare’s list of venue names, and all that venue data is available under a liberal license... He points to SeriousEats, the recipe and food blog network, which debuted a new feature at SXSW called “NearMe.” It grabs the reader’s current location, then recommends restaurants, Food Truck-s, and other nearby food choices. If the Serious Eats reader is also logged in to Foursquare when they visit the site, they get personalized recommendations based on their friends’ favorites. This personal touch is powered by Foursquare’s more robust Explore API rather than the simpler Venues API, but it adds a ton of value to Serious Eats’ readership, who also happen to be Foursquare users.

Bill Seitz