Every parent’s “talk” with their kids should start with “Never say or post anything about yourself on the internet, in any capacity, that you wouldn’t want literally everyone in your life knowing about.”

I would extend that to include even uploading things to private cloud servers and saving things to your own computer. You don’t have to take these precautions, but then it’s on you to deal with consequences of people seeing the things you want to keep private. Sure, there can be bad people who make extra effort to find and share your private things, but if you already covered your bases ahead of time by not saying things you don’t want others to hear, not posting media you don’t want others to see, you can make it almost impossible for people to cause you harm this way. Also, don’t talk about war plans in group chats.