Twitter's about to unveil a new feature that taps into another developing social networking trick: Geolocation. The ability to pinpoint your location will happen automatically within the Tweet's code, and it has some big implications.

The initial roll-out will be via some specialized API hooks for developers, which means that it'll be achieved through a Twitter client app on your smartphone at first, which is a sensible choice, given these gizmos mostly have GPS functions nowadays, or at least use Wi-fi approximated location detection. It will also be an opt-in service, with location detection defaulting to "off" for privacy reasons. Again, that's sensible--it's all very well to vent your spleen about crappy service in a shop on Twitter, but you may not necessarily want to precisely identify which one. Twitter is also promising not to retain the exact geolocation data "for an extended period of time."

This will start simply, with each Tweet's geolocation (shall we call it a Perch?) more of a curio than anything else. But that can't last long, as the location-based info is likely to become amazingly useful. It starts with simple Augmented Reality--and with the Twitter-locator service Twitaround (shown in the video) and Tweetmondo on Layar, which previously just let you locate a Tweep's approximate base location. Soon these systems will let you see individual nearby Tweets in real time, opening up all sorts of interesting social networking angles (as anyone who uses Foursquare can tell you). Biz Stone, announcing the new service on Twitter's blog noted that it will also be useful if you're tracking an event like "a concert or even something more dramatic like an earthquake." He's right, Twitter-based news gathering is going to get more interesting with geolocated Tweets.

But there's another potential angle that may or may not be as welcome: Location-based ads. Advertising per se apparently isn't in Twitter's future, but there's nothing to stop a clever app developer to team with local businesses to spot nearby Tweets and then invite the Twitterer to sample their services. Geolocation allows all sorts of amazing opportunities like this, and most of them we probably can't imagine yet.

[Twitter Blog]