One of the features of Stripe that really impressed me on my first visit was, since I don’t know if it has an established name, what I’ll call the Anonymous User pattern. If you go to Stripe.com and press “Get Started with Stripe”, you can try out a fully-functional Stripe account without ever entering a username, email address, or password.

http://roshfu.com/2012/01/16/the-anonymous-user-pattern.html