Twitter has added a new feature that can make the service more relevant. In the right-hand navigation bar, under "Trending," you can now select a geographic region to see what's hot on Twitter in one of a few cities.

Only 15 U.S. cities and five non-U.S. countries are on the locality list, although it's very likely that Twitter will add more locations shortly.

Twitter last year rolled out a geolocation API, which lets posts from Twitter apps--but not the Twitter.com site--tag each Tweet with the location where it was made. Presumably,Twitter posts from the site itself inherit their users' static location from their profile page.

More: http://news.cnet.com/8301-19882_3-10441825-250.html