It's bollocks. @GidMK did a lovely post on it. I'll forward.
As an investigative lab study, it was ok, but extrapolating to anything else is terrible!
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
As an investigative lab study, it was ok, but extrapolating to anything else is terrible!