social networks, are they really safe

People use social networks for various reasons like keeping in touch with friends, knowing what their former school mates are doing at present and some to look for friends. When you sign in on these networks you are required to fill in your details which is usually known as ones profile. by doing this you have given the people who visit your profile your identity. Is there privacy in these networks since anyone can get hold of information such as where you stay, how old you are and many other things which can only be known by people who are close to you. Ever heard of cyber criminals, these people are criminals who do their crime by finding their victims on the internet. They have been reports of kidnappings and murders by people who get all the information from the different social networks. People with different fantasies get hold of other peoples information and those who are unlucky can have stalkers on the net and they might even be in the same area as them. Are we really safe on these networks with crime taking place when you have a password to access your account but at the end of the day people get kidnapped ,murdered and some stalked by people they do not know.