How do I keep my 11 year old sister safe from online predators?

[Couman]

The most important thing to keep in mind is that nobody can hurt you over the internet. You are 100% protected to start with. But every piece of information you give out makes it just a little easier for someone to find you in real life. So it only makes sense to guard that information very carefully.

And of course if you intentionally meet someone in real life you have given up that protection completely. That might seem too obvious to even mention, but the fact is that is exactly how most online predators operate. They convince people to meet on purpose. So it bears repeating, don't do that!