Cyberbullying is indeed a very serious issue. Many people have committed suicide for this exact same reason. Do you recall the story of the girl who killed herself because she was bullied on Myspace?
However, cyberbullying can not only be reported, it can even be charged. For example, if the cyberbully posted nude pictures of the victim without their consent, the bully could be charged as a sex offender.
For more info on cyberbullying, take a look here. [link]