If I limit a post's audience to just friends from high school, for instance, Facebook will make that the default audience setting on all of the posts I make from then on. As a result, many of those users may have unknowingly published posts as public that they intended only for certain friends.
Facebook has revealed that up to 14 million of its users had their privacy settings accidentally changed by a software bug - causing some posts that were meant to be private to be made public.
Ms Egan says the issue did not affect past posts and has apologised for the mistake.
Facebook said it was testing out a new feature - one that would suggest people share featured profile items publicly, but it accidentally set the default for posts to "public" as well.
It could be. Jonathan Mayer, a professor of computer science and public affairs at Princeton University, wrote on Twitter that this gaffe "looks like a viable Federal Trade Commission (FTC)/state attorney general deception case". They'll receive a notification on the app or the website and a link to a list of anything they shared during the "oopsies" window.
In its most recent trouble, the company revealed it had been sharing data with partners in China, which happens to be the last country most privacy-conscious users would want to share data with. Even if the bug was an accident on Facebook's part, Mayer said in an email that the FTC can bring enforcement action for privacy mistakes.