Facebook is meant to represent real people and real associations; it's also meant to be safe. Many of the rules of participation on Facebook exist to uphold those two goals. This list is by no means exhaustive—there are plenty of things you can't do on Facebook, and even more that you shouldn't do.
You can't troll. Facebook is about real people and real connections. It's one thing to message a mutual friend or the occasional stranger whose Profile implies being open to meeting new people if the two of you have matching interests. However, the moment the people you contact have a problem with you sending unsolicited messages, your account is flagged; if the behavior continues, your account is deactivated.
You can't be twelve or younger.Facebook takes very seriously the U.S. law that prohibits minors under the age of 13 from creating an online Profile for themselves. This rule is in place for the safety of minors, and it's a particular safety rule that Facebook takes extremely seriously. If you or someone you know on Facebook is under 13, deactivate (or make them deactivate) the account now. If you're reported to the Facebook user operations team, your account is deleted instantly.
You can't upload illegal content. Respecting United States law is something Facebook has to do regardless of its own position on pornography (where minors can see it), copyrighted material, hate speech, depictions of crimes, and other offensive content. However, doing so is also in line with Facebook's value of being a safe, happy place for all people (older than the age of 12). Don't confuse this with censorship; Facebook is all about freedom of speech and self-expression, but the moment you compromise anyone's safety or break any law, disciplinary action is taken. (c) by Suzanne Havala Hobbs from Living Dairy-Free for Dummies
to be on - быть онлайн, to sign up - зарегистрироваться, to sign in / to log in - войти/залогиниться...
более двух десятков выражений в посте * действия в социальных сетях.