Remember how I was ranting the other day about how way more devs use Windows than you think? Turns out to be true.pic.twitter.com/PoeJdU0VSd
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
Umm, very difficult question and my answer would probably be skewed by my experience. I don't think we have a decent way of knowing, as the platform choice usually is constrained by the tech being developed/used.
I'm willing to go out on a limb and say that many developers use Windows.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.