Public vs private information

Private information is kept to your self like a secret and you dont want anyone to know about. Public information can be shared with others on social meadia. 

Private information shouldn't be shared on social media for example: your personal address, or your account details.

Public information can be shared on social media for example: pictures of harmless thing, or liking puppy videos. 

If private information is shared with friends it can be shared with others, brocasted, stolen, or posted permanently.