Social network: websites like Facebook and Twitter which host online “communities”. The popular film about the creation of Facebook was called “The Social Network”.
Troll: noun to describe people who use the Internet to post offensive and abusive messages, often in the form of bullying.
Cyber-bullying / cyber-psychology: “cyber” is like a synonym for “online” so these words refer to bullying that takes place online, and the study of behaviour (psychology) of people online.
Please see this BBC article for examples in context:
Hi Ritika you're absolutely right! Many new "cyber" concepts have been born with the Internet.