A single form can prevent customers from purchasing products from major e-commerce sites. "The form was simple. The fields were Email Address and Password. The buttons were Login and Register. The link was Forgot Password. It was the login form for the site. It's a form users encounter all the time. How could they have problems with it?"...

Fascinating study piece on getting buttons, tasks & actions right in checkouts. The solution: the designers took away the Register button. In its place, they put a Continue button with a simple message: "You do not need to create an account to make purchases on our site. Simply click Continue to proceed to checkout. To make your future purchases even faster, you can create an account during checkout."