Goo.gl, the URL shortener Google launched last December, is now publicly available and can be used for any links on the Web. Google is actively touting the stability (near (100% uptime since launch), security (Google added automatic spam detection, the same filtering available in Gmail and Speed. 

From the blog post: There are many shorteners out there with great features, so some people may wonder whether the world really needs yet another. As we said late last year, we built goo.gl with a focus on quality. With goo.gl, every time you shorten a URL, you know it will work, it will work fast, and it will keep working. You also know that when you click a goo.gl shortened URL, you’re protected against malware, phishing and spam using the same industry-leading technology we use in search and other products.

Perhaps the most interesting feature is the built-in tracking. If users sign-in to their Google account, they will see a list of the URLs they have shortened in the past. Click "details" and you'll find public, real-time analytics, with traffic over time, top referrers and visitor profiles.