Online social networking have predators on them. Some years ago a girls was killed. She was raped and killed by this 35 year old man. The man told her to meet at a disclosed location. He convinced her to meet him there. Her parents found out by looking on her computer were the two had been exchanging messages.Thus showing  what could happen when your online socializing.
Harrassment can be done during online soacializing . A 15 year old boy was harrassed by some seniors at his school. The boy went ro the hospital after being depressed for so long. The doctor  said the boy constantly talked a bout suicide. A few weeks later he dropped out. Thus showing  what people can do whatever to you through online networking.
The number 1 problem with online socializing is cyber bullying . A student stopped going to school all together when kids started cyberbullying him. He tried to avoid it and ignore it but they wouldnt stop.
He stayed depressed a lot. His life has never been the same since then. Thus showing social networks can cause mental harm to innocent underserving people.