An interviewer for a very popular teachers' journal asked me to tell her what can be done when a "mean girls" cyberbullying campaign has begun to get the bystanders and those within the "mean girls" circle to stop it.
Unfortunately, getting in the middle of an active "mean girls" cyberbullying campaign is like trying to separate fighting dogs. If you aren't careful, you will be bitten. Instead of asking our teens to step up and try to take the cyberbullying heads-on, we advise them to report it to the network, school, their parents or the authorities. Their anonymity will be respected by the networks. There is a greater chance that their reporting it to school, parental or law enforcement authorities will be disclosed somewhere along the line. Sometimes just walking into the principal's office or guidance counselor's office is enough, if the "mean girl" actors are called into that same office shortly thereafter.
Frequently, in a mean girls cyberbullying campaign, the "mean girls" will turn on anyone who fails to support their campaign. As well-intentioned as it is to tell teens to "stand up to their bullies," or "take a stand against a cyberbully" this only puts them in danger.
This is why we recommend an anonymous reporting service, where the students can report it to an organization who will in turn report it to the school, as well as providing support or a report can be made without tracking the reporter.
Note that when reporting cyberbullying or other cyberabuse incidents to the networks, you should ask them to retain all data so that law enforcement investigators can pull needed evidence. Otherwise, the data may be lost entirely. If you are working directly with law enforcement, they can serve a "data retention letter" on the network, to preserve data that might be deleted by the user or taken down in response to an abuse report.
Some of our Teenangels, my cybersafety expert teens, have suggested blaming it on your mom. "Sorry, I can't join in. My mom is watching everything I do online." "My mom said that if she sees any cyberbullying, she will take away my FB page" etc. If all fails, blame your being respectful and acting responsibly online on your mom. :-) We get blamed for everything bad. Might be nice once in awhile to be blamed for something good.