The Fastest Registration Ever: Friend.ly
No wizards. No forms. No Facebook Connect or Twitter Oauth popups. No typing at all.
A single click is all you need to sign up for friend.ly. After that, you’re in, with a profile including your picture. You’re connected to friends. You have pre-filled questions to answer based on your interests, as well as pre-filled questions to ask your friends based on their interests and mutual connections. There’s a leaderboard of your connections. You’re in. One click.
This is accomplished via Facebook’s registration plugin, and I’ve never seen it implemented so well. It assumes you have a Facebook account, and works best if you’re logged in to it. For a social app like this, that’s a pretty fair assumption.
Perhaps that’s why their early traffic numbers are looking, well, smoking hot.