The New York Times covers Twitter's planned release of geolocation data. The new feature will take advantage of geolocation data in cellphones letting users include their location in tweets.
This will allow users to search Twitter by location, improving its use for location applications like local commerce. It will also allow comparisons across geography. For example you could compare what people in New York tweeting about swine flu versus people in Texas.
More evidence of the growth of the local web.