Just received a book in the mail and gasped when I realized where it's been before I got it, and who used it.pic.twitter.com/9vdTkokS2i
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
Probably recalled it from each other (I used to work in a college library, profs did it all the time).
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.