Google's own URL shortening service Goo.gl has finally went public. Now, if your response to that would be some thing like, "What? Wasn't it public since last year or so? Haven't you been seeing Goo.gl links all over Twitter? How then can a service "go public" even as it was being used for the past few months?" then please let me explain!
You're right. You have been seeing Goo.gl links all over the place. But let me ask you, were you able to auto shorten URL's of your choice until now? You have been clicking, clicking clicking, right? Until now, certain Google applications were the only ones allowed to use the Goo.gl short URL. That service is now open for the public at large to try out now. Quite a difference, eh?
Goo.gl has in its sight already popular URL shortener's like bit.ly and is.gd.
Goo.gl has been around since December 2009 and it has taken almost an year to reach a public launch. If you're still wondering as to what more features does Goo.gl offer over others, here are a few:

How about automatic spam detection, and “near 100% uptime since our initial launch,” as claimed by the company? Bit.ly and a few others have been known to face downtimes in the past. Like the others, Goo.gl also gets URL-tracking features using which you can view URL history, traffic sources, referrers and visitor profiles for countries, browsers and platforms.
Anyway, you might want to head here and try the product without any further delay.