Do you remember two months ago when Facebook usernames went live? Millions of avid Facebook users waited on a Friday night for the chance to claim their own custom URL. 200,000 were claimed in 3 minutes, 500,000 in 15 minutes, a million within an hour, and 3 million usernames by the next morning.
Still, that's just a tiny portion of the nearly 300 million users of the world's larger social network. However, it looks as if adoption of usernames hasn't stopped. According to a recent note from Facebook engineering, it was revealed that the company has reached over 50 million users. And that milestone was passed several weeks ago - there's no telling how many people have registered a vanity URL by now
In a post entitled "Designing the Facebook username land rush," Facebook's Srinivas Narayanan reveals the number while explaining the difficulties of building a system capable of handling 200,000 signups in 3 minutes and planning for contingencies (aka the so-called "nuclear option"). These are subjects we actually discussed with Facebook's Jared Morgenstern and Guy Rom at Facebook headquarters the night of the launch.