If you share links in emails or the social web, here are three reasons why bit.ly will win your heart:
1. bit.ly creates a mirror copy of the underlying web page at the time of compressing the URL (see example).
That means there won’t be any orphan short URLs because even if the target page is offline or removed from the web, you can still access that information from bit.ly’s cache.
2. With bit.ly, you get to know the exact number of times any particular short URL was clicked on the web be that inside email messages, IM clients or regular web pages.
3. Other than counting clicks, bit.ly all tracks the referrals so you know exactly where the clicks are originating from. (see example)