FACT CHECK:   Can Facebook users check if their accounts have been hacked by commenting “@[4.0]” on posts?

Claim:   Facebook users can check if their accounts have been hacked by commenting “@[4.0]” on posts.


Example:   [Collected via email, September 2015]

Go onto a photo on Facebook and type in the comments @[4:0]. If it changes to Mark Zuckerberg it means your Facebook hasn’t been hacked.

Mark Zuckerberg is the creator of Facebook…

This is new to me. Is there any truth in it?

Origins:   In September 2015, a rumor started circulating via Facebook claiming that users of the social network could check to see if their accounts had been hacked by commenting “@[4:0]” on photographs. If the code turned into the name “Mark Zuckerberg” when posted, that supposedly meant the posting account had not been compromised:

While typing @[4:0] on Facebook will often result in Mark Zuckerberg’s name appearing (results vary depending on operating system), this is not the result of a Facebook security check. This trick has more to do with code, Facebook’s mention system, and Mark Zuckerberg’s site ID than it does with hacking.

In 2011, after a similar trick (explaining how a long string of numbers followed by the @ symbol could turn into the words “I’m Gay”) went viral, USA Today reporter Rosa Golijan explained that the numbers following the “at” (@) symbol simply corresponded to the ID number of a particular Facebook user or Facebook page:

The “@” symbol and surrounding brackets instruct Facebook to convert the ID number into the page’s title in a comment or Wall post.

In this case, since Facebook founder and CEO Mark Zuckerberg’s Facebook ID number is 4, the “4:0” corresponds to his account and is replaced with his name when inserted into a Facebook post.

Last updated:   8 September 2015

Originally published:   8 September 2015