Twitter announces GeoLocation API. Track tweets by location

From the Twitter blog: "We're gearing up to launch a new feature which makes Twitter truly location-aware. A new API will allow developers to add latitude and longitude to any tweet. Folks will need to activate this new feature by choice because it will be off by default and the exact location data won't be stored for an extended period of time. However, if people do opt-in to sharing location on a tweet-by-tweet basis, compelling context will be added to each burst of information"