Facebook makes it convenient to tag your friends or pages you like on a status update. However, Facebook also has privacy settings that allow you to hide an update from groups of people or a person. Combine these two features together and you have a mischievous bug.
Essentially what the bug allows you to do is place a hidden message on a friend or businesses profile page that everyone can see except for them. Usually your friend would be able to view the post on your wall as well, but that is also hidden. The only thing that the tagged person gets is a notification, but when you follow the link it results in an error page.
The Bug
As pictured at the beginning of the article, you will notice that I have tagged play-this mag’s profile into a status update. Clicking on the lock next to the share button will display the option to edit the custom privacy settings of that single post.
The custom privacy setting prompt will appear and under Hide this form you place the tagger users name. Hit Save Setting and the prompt will close. Hitting the Share button will then post the tagged message.
As you can clearly see, the tagged message shows up on my profile, but not on play-this mag’s. Play-This Mag will get a notification, but when you attempt to click on it an error will appear.
[Thanks for the tip @lmsherwin]
I am a Communications Marketing Specialist for GovWin, a social media addict, the founder of a communications consulting firm that offers free assistance to the world, and dedicated to empowering everyone. 
