Not entirely related to the product, since I am midway through the signup but something about the Auth that I thought you should take a look at right away; more so when you say Pinterest for "programmers" :)
A password field that's a text field?
A password field that's a text field?
And there the point to stop taking that article seriously.
The MS Solution is good though. I think it is the best. Better than the android/iphone flash up the last char for a second thing.