Cyber-bullying, also referred to as electronic bullying, can be defined as the repetitive and willful harassment through the use of the Internet, mobile phones or other forms of interactive and/or digital communication, usually with the intent to humiliate, torment and threaten an individual in order to assert the perpetrator's power over the victim. This kind of bullying is limited to children, pre-teens and teenagers. If a similar type of aggressive behavior happens to an adult, it is labeled as cyber-harassment or cyber-stalking. All forms of cyber-bullying can be classified as a computer crime punishable by law. Unfortunately, unlike traditional bullying, cyber-bullying is difficult if not impossible to trace. This is because the youthful perpetrator can remain anonymous online, supply false identifying information or constantly change online personas.

According to a 2005 study, cyber-bullying can take different forms, such as sending mean, vulgar, or threatening messages or images; posting sensitive, private information about another person; pretending to be someone else in order to make that person look bad; and/or intentionally excluding someone from an online group. This is usually done through e-mails, instant messaging (IM), text or digital imaging messages sent on cell phones, web pages, web logs (blogs), chat rooms or discussion groups, and other information communication technologies.

Traditional bullying is distressing enough; however, cyber-bullying is even more terrifying because the harassment can occur continuously at any time of the day or night, with the messages and images distributed quickly to a very wide audience. With the advent of camera phones, perpetrators can take pictures of their intended victim in compromising positions and post it on the Internet. Examples of these can be seen in websites such as YouTube which allows members to post pictures and videos online and subsequently viewed and downloaded worldwide. It may also be circulated through e-mails in the form of attachments. This increases the humiliation felt by the victim, often heightening the stress and anxiety they feel.

Research suggests that more girls are victims and perpetrators of cyber-bullying. Experts suggest that this is because of the passive-aggressive nature of the crime. Unlike boys who can often express these feelings in physical outlets, girls are denied the same privilege for their feelings of anger and aggression for fear of being seen as unfeminine. While cyber-bullying can be violent, this violence is mostly non-confrontational and non-physical, and can be carried out regardless of the size or age difference between the victim and the perpetrator. What matters in this case is the particular expertise in using these information communication technologies. So now, the stereotypical nerd can bully those that may be physically bigger or stronger than they are because they are more technologically-savvy.

Although most victims can opt to ignore the bullying, this will not work for all cases. Unfortunately, because of the nature of the Internet, publishing or posting a defamatory pictures or statements against the victim is extremely difficult to prevent, and these can be viewed or downloaded until it is taken down. Other options would be to change the victim's email address and/or mobile phone number. The best action to take would be to report the incidence of cyber-bullying to an adult, taking care to present the proof of the harassment, in the form of saved mobile messages, e-mails, or videos.