Bitly is one of the oldest and largest link shorteners, meaning you can trust that it won't go away anytime soon.

You can set up bitly to use a custom domain, so you don't have to develop or maintain your own.

When people see a bit.ly link, they don't usually think, "ooh sketchy link".

The bitly API provides jsonp callbacks, XML, CORS, and data metrics. The API is simple, and easy to use with good documentation. It is clearly thought out and is up to date with support for new API technologies.

Bitly provides bit.ly bitly.com and j.mp

If character count matters, you cannot get a domain shorter than j.mp

Anti spam measure and tools mean people that follow your bitly links can be confident that they won't lead to a dangerous site. Bitly links cannot be changed, meaning a trusted link will stay safe.

Bitly has a bookmarklet for creating short links very quickly.