Read, reading, to be read. (Research for the book. The right pile is likely to grow, still.)pic.twitter.com/MFnPLZOCrn
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
(The yellow pages.)
I've only seen that web page about it that I linked to.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.