Direct Action

Try this if you're invited to join a cyber fight:
"I totally understand that you are having a problem with this person, but I can't get involved. I'm not going to talk to [the suggested target], either. No matter what happens between the two of you, things between us will stay the same."

What to say when you're in the fight:
"I really don't want to talk about this online. I think it's easier to talk over the phone or in person. Can I call you right now? (or, Can we talk tomorrow at school at [suggested time]?").

What to say when someone tries to involve you in bullying:
"I don't feel comfortable doing this (or "I'm not cool with this"). Let's talk later."
or
"Check out this amazing [website] [download] [song] [video]!" In other words, change the subject.