There are several major dangers that one can face on the internet. By and large, they differ little from those that threaten us in real life. The attackers here are simply using other means.
Bullying. The child is called names or bullied on the Internet – most often for no reason, “because it’s so much fun.” The victim can be stuck on because of a profile photo or a post on social networks.
Pedophiles. They ask to send personal photos, and if they refuse, they threaten reprisals against family members or blackmail them in other ways.
Scammers. They are trying to take possession of user data or involve a child in a dangerous financial adventure.
The main defense against all of these threats is confidentiality. You cannot upload your photos to the Network. You should restrict access to information about all aspects of your life, whether online or offline. You can communicate them only to trusted people: relatives, friends and people who are familiar to you personally, and not through the Internet.
Those who are trying to hurt and offend you in some way (the so-called trolls) should simply be ignored.