Why is it that many young girls still try to impress random guys online?

[Gladius]

I think a really important thing to remember is that in some ways the internet really is very safe, but sometimes that safety can make you over confident.

No one can physically hurt you over the internet, so in a sense you are completely invulnerable. But that only lasts while are on the internet. As soon as you meet someone in person, or give them enough information to find you in real life, that invulnerability is gone.

Facebook deserves a special mention. Because people interact with their real-life friends and family there, they might think of it as safer than most parts of the internet, but it's actually more dangerous for just that reason. Facebook isn't as separate from the offline world as most sites are. Someone can very easily find out where you live, spread nasty rumors to your real friends and family etc.

So: #1, see above. #2, no. As I explained, talking to strangers isn't the dangerous part. It's the people who aren't quite strangers that you need to be super careful with. #3, explain that on non-anonymous parts of the internet, you have to be just as careful as in real life, because the consequences are the same.