Here is some advice from an internationally acclaimed expert in the area: Professor Sheri Bauman, from the University of Arizona.
She writes: As technological devices have become more widely available, misuse of the devices has become a problem affecting young people. Cyber bullying refers to behaviours that are intended to harm others using technology, by hurting their feelings, causing embarrassment or humiliation, damaging reputations, and disrupting relationships. Some acts that appear to be cyber bullying may originate because of misinterpretation, miscommunication, or misguided attempts at humour. We know that cyber bullying is less prevalent than traditional bullying, but has many of the same consequences: depression, anxiety, absenteeism, reduced concentration at school, increased risk for suicidal behaviours etc.
Although traditional bullying has occurred for eons, cyber bullying has the potential to be more harmful because of its unique characteristics: