Over the last few weeks I’ve been using tr.im to quickly shorten URLs that I post to Twitter. It that provides all kinds of great statistics on the shortened URLs that you create, including the number of visitors, visitor country locations and referring websites. You can create custom urls, private urls and the ability to post directly to Twitter. Oh and it makes super short URLs, since tr.im itself is a four letter domain.
Big shout out to @dlprager for turning me on to tr.im.