Credit: CC0 Public Domain Facebook for the first time published its secret rules and guidelines for deciding what its 2.2 billion users can post on the social network.
Here's some of what you can't post:
Uncovered female nipples. Exceptions: images of women protesting, breastfeeding and post-mastectomy scarring. Never allowed: squeezing a naked female breast except when breastfeeding.
Nude posteriors. No visible anus or nude close-ups of buttocks are allowed, unless they are photoshopped on a public figure.
Erections or implied sexual intercourse: No actual or implied intercourse (mouths or genitals entering or in contact with another person's genitals or anus, even when that contact is not directly visible) except in the context of sexual health, advertisements and recognized fictional images.
Fetish content that involves dismemberment or cannibalism.
Nude photos of kids (even by parents). And no uncovered female nipples in photos after "toddler age."
Crime confessions: Don't fess up to theft or sexual assault. But you can debate or advocate that criminal activities be legalized.
Trying to buy or sell marijuana or other drugs. Don't even express an interest in buying or selling drugs.
Claims that a victim of a tragedy is acting, pretending, lying or being paid to lie. It's considered a form of harassment.
Insensitivity. Your posts could get removed from Facebook if you target someone's vulnerabilities such as disease, disability or premature death.
Dismemberment, visible organs, charred or burning people or victims of cannibalism unless it's in a medical setting. And if you do show graphic violence that is permitted because it's a form of political speech or newsworthy, it will come with a warning screen and the content will be limited to adults 18 and over.
More on what you can't post on Facebook here.
Explore further: Facebook rules at a glance: What's banned, exactly?