All types of bullying them is same,that is influence to someone and force,typically to do something.The person who bullying other in the feeling of jealousy,fear,
distrust and the overall need for a popular image.The person who face physical,
mental,or verbal abuse at home tend to copy these behavior with others the same
Here we are looking for proper tools to study Cyber-bullying, like Questionnaires. If you have in mind such tools from the academic literature let us know here in this public question.
You could use questionnaires about anxiety or depression to assess the level of upset. You could also use questionnaires about trauma.You could assess the victim's social skills using SSIS.(see my book on social skills). You could analyse the content of the bullying material e.g physical threats, verbal abuse, psychological attack.
Good luck, that is a very interesting area to research!