The only information on there is the information you put on there. A lot of people don’t check email anymore. Social Media is the primary means of communication.
Not entirely true.
If you install the app on your smartphone, as soon as you sign in to FB with it, the app uploads all the contact info from your phone book.
All the contact info.
The phone numbers of your mistresses on your phone? FB knows you know them.
Your siblings who refuse to be on FB? If you have their contact info in your phonebook on that phone, well FB now know about them and that you are somehow connected to them.
It's naive to think social media only has what you post on it and nothing else.
It has more on you than you care to know.