I don't have a twitter account and I'm not going to sign up just to try something out. I don't want to be mean, but the point of a "try it in your web browser" is that the barrier to entry is low. Twitter makes it high again.
My twitter account is, like my facebook account and my google+ account, private to those whom I know and trust. why would I give that information to some random website?
My guess is that it is a version of the Flask-OAuth extension sample app, found here:
http://packages.python.org/Flask-OAuth/
Flask is really great, BTW.