Ever since social media sites like Twitter required people to keep their online messages ultra-short, people have been using web address URL shorteners to make room for more content. Google jumped on that bandwagon nearly a year ago with goo.gl but it turns out that wasn’t quite short enough; the company has now launched g.co.

At only 4 characters, you couldn’t possibly find a shorter URL. Google says this new URL shortcut will be used for many of its online properties; that presumably includes its new social network Google+.

The g.co URL isn’t available for public use. Google just announced the new domain on its blog today. For now, just know that any time you see a “g.co” in a tweet that means a web link to Google-hosted content is present. You might get to use it yourself in the future, or you might not; we’ll just have to wait and see.

There are several other options for URL shorteners that help you to share your content on Twitter. Some URL shorteners like bit.ly allow the people who use them to track analytics like how often the addresses are clicked. Given Google’s own savvy with web analytics, we wouldn’t be surprised if Google plans the same — if it ever makes g.co public.

Twitter shortens links on its own, but this functionality doesn’t offer the analytics tools that third-party shorteners offer.