Web forms have come a long way over the last few years, from bland and lifeless labels with input fields barely better than paper forms, to interactive and beautifully designed experiences like huffduffer. New technologies like inline validation have really helped web forms become far more intuitive and easier to use, providing timely and helpful feedback to users as they move through a form.
Inline validation, when used correctly provides immediate feedback next to the input field showing that the field has been filled out correctly or incorrectly, without the need to press submit and waiting for the error message. The example below is from audible, having finished typing in the username field and tabbing to the password field, I was informed that my username had already been taken allowing me to immediately select an alternative. This saves me time and prevents me getting to the end of the form, pressing submit and only then finding out the username was already taken. Read more