This is when the internet and the mobile phone is used to deliberately upset someone.
For example by sending nasty messages by text or email. Or posting messages meant to be private on public places like Facebook, Bebo or Myspace in order to embarass or upset someone.
Some figures show that nearly 2 in 3 schoolchildren have suffered cyber bullying at some point.
The best advice when this happens is to contact a parent or teacher to let them know it is happenning. They will be able to make sure the bully is dealt with.
Challenge see if you can find out one extra fact on this topic that we haven't already told you
Click on this link: Cyber Bullying