If it goes about facebook:
Facebook is a poop but tons of people use it, place their photos and they don't use other communicator... so there lasts either contact via e-mail that is less comfortable or just f2f(sometimes not possible). I accept using facebook to chat and keep in touch with old pals but.. we have to set a line of privacy we won't cross. You know that even if you delete your photos you placed there, facebook manager has still a possibility to see them. They don't vanish. Chats too, so talking about everything is rather stupid - we can consider someone hacks your account what's so easy. What's more, you agree that information about you can be used. So "hiding" anything doesn't change nothing. You can harm yourself.
Another
er is that people are addicted to it. Lot of girls have it launched on their mobile phone and they refresh it every minute to see if someone like their hamster... or dead hamster, everything can be liked what's a stupidity btw. And such girls spend hours doing nothing or like in the video haas found - publishing private stuff about family, themselves. Such girl leaves a lot of information about her and her family so for stalkers who have some hacking abilities possibilities of blackmailing or other things are countless. Be aware.
PS: I said "girl". But it can be even a boy, just was an example, so no offence.