Facebook went offline briefly on Thursday to fix an updating slip.
"For a brief period of time, some internal prototypes were made public to a number of people externally," a Facebook spokesperson said in an email reply to an AFP inquiry.
"As a result, we took the site down for a few minutes. It's back up, and we apologize for the inconvenience."
The problem reportedly occurred while Facebook was revamping pages for businesses at the website, which boasts more than 500 million users.