Loopt, which combines geolocation with social networking, is available for the iPhone, BlackBerry, Android, and many other phones (full list). Like other services, Loopt invites you to check in to locations and share what you're doing with Facebook and Twitter friends, next to your own network of Loopt friends.
Loopt also provides an event directory called Pulse, where you can browse various listings categories (such as movies, gigs, and shows) for things going on near you--and afterward leave ratings and tips. Freebies and special offers are available too, indexed from nearby retailers.
Google, Facebook, and Twitter Join the Party
With such a burst of interest in geolocation, it's hardly surprising that social-networking giant Facebook and ever-growing Twitter are getting involved. Last year Twitter introduced its geolocation API, which allows third-party developers to incorporate the feature into their apps. Many Twitter smartphone clients, such as Twitterrific or Tweetie, nowadays let you attach your current location to your tweets, and so do some of their desktop counterparts.
Twitter has recently introduced the same feature on its Website. Using geolocation from Twitter.com is not as seamless as with services like Foursquare or Brightkite. First, you have to opt in to the feature, and currently it works only with Mozilla's Firefox browser. The Twitter service lacks check-in features and offers no incentives, such as badges or points, when you share your location. Right now, the only way to view the location information attached to a tweet is via a Google Maps overlay; but you can use Twitter's advanced search mode to search for tweets from around a certain location, such as a city.
Facebook is expected to make geolocation features available to its 400-million-plus users sometime in April, though details of the implementation remain undisclosed. Given that more than 100 million Facebook users update their status from mobile phones, however, the potential popularity of geolocation on that network is huge.