Most importantly, we talked about being nice. She loves to draw, play, and take care of people. She also has a temper when provoked, so we talked about how being nice, whether in person or online, won't lead her down the wrong path. We talked about how she should never hit back or say mean things, even when the other person deserves it.
It was good to talk to her, and I feel that's something that all parents or responsible adults should do. Granted, I am being idealistic in this regard, but shouldn't we teach kids to treat each other with respect?