Facebook, the online social network used by more than 500 million people around the world, went down briefly Thursday after the site miscued the introduction of some new features.

“For a brief period of time, some internal prototypes were made public to a number of people externally,” a spokeswoman for the company said. “As a result, we took the site down for a few minutes. It’s back up, and we apologize for the inconvenience.”

Messages on Twitter and technology blogs put the outage at about 15 minutes, around 3:30 p.m. Central time.

Downtime for Facebook, which is relatively rare, not only affects users, but also can hurt other sites and advertisers dependent on traffic from links in Facebook.