Gowalla 3.0 for the iPhone includes a deep integration with rival location-based service Foursquare, though the two companies did not work together to get it done. Gowalla set up the integration through the API, which means that its larger, more well-known competitor was probably as surprised as anyone when the new version debuted in the iPhone app store on Thursday.
That leaves Foursquare with few choices as to how to react to the move. It could block Gowalla's use of the API altogether, which could wind up causing more trouble for the company in the end; or it can let Gowalla use the API at the risk of hurting its own business. Or, Foursquare could even add the new integration into its own app.
Currently, the integration lets Gowalla users broadcast their location check-ins on the iPhone app, on Twitter, Tumblr, Facebook Places and Foursquare, and even lets them earn Facebook Deals and Foursquare Badges through the app. Gowalla has also introduced a new interface where users can view all of their friends' movements from a Universal Activity Feed, which is an aggregated stream of checkins from not only Gowalla but also Foursquare and Facebook Places.
This alone gives Gowalla's app the most comprehensive universal check-in feature on the market.