Don't just stand there. Do something.
Watched this movie with my daughter (12 yrs old): http://abcfamily.go.com/movies/cyberbully
She is online - on facebook, texts and IMs as the primary means to communicate with her friends, and is very involved in her social group. She really liked the movie - she thought that it was very possible / plausible. I think that part of what she was saying (nicely of course) is how clueless the teens' parents were about what really happens in the social network of the teens. And from her perspective, that it would definitely be a catastrophe to be the target of cyberbullying. Maybe even enough to end your life over - particularly because ".... no one (none of the adults) would have a clue how bad it was ...."
Talk about a dose of reality. That the primary task of teens - to separate from parents and other adults - leaves them completely isolated when bullied by their peers thru modern technology. And the desperation of being isolated both from adults and their peer group - is enough to drive a teen to suicide. Wow. In that very short conversation with my daughter, I could see the desperation to belong and an outcome of essentially being shunned by their peers.
So, I asked my daughter what she thought parents could do to help prevent both cyberbullying and to help a teen if they were either the target or perpetrator. My daughter rolled her eyes at me and said: "Mom. Its simple. Just keep talking to me .... no. Just let me talk to you ..... I need to do it lots over stuff that doesn't matter if I'm going to talk to you about something like this."
Strongly recommend the movie for parents to watch with their kids - to use as a springboard for discussions. What is cyberbullying? What would you do if one of your friends was a target? What if you found out they were the bully? Can you be friends with a bully? How? What if your friend is being bullied and won't talk with an adult?