Dribbble is show and tell for designers, developers and other creatives. Share sneak peeks of your work as “shots” — small screenshots of the designs and applications you’re working on. It’s also a place to talk design, give and receive feedback and iterate toward better work.

However, there is no sign up for Dribbble at this time. Membership is entirely driven by existing users – all members of Dribbble have been drafted (invited) by other members. Dribbble has a narrow focus on high-quality design work. They know there are many fantastic designers who have not received an invitation. But it allows them to grow the content and community at a pace where they can preserve the Dribbble ethos.

Source: http://dribbble.com/