Bitly is a simple url shortening service aimed at web professionals. The service provides a simply shortened URL and friendly urls based on keywords you specify. This is an example of a single-serving site that provides a simplified interface, but offers much more functionality following that initial interaction with the service. Attention is paid to making default behaviors easy, but gives expert users much more below the surface. bit.ly also offer referring tracking, an API for web apps, mirrored URL on Amazon Web Services, and thumbnail images.