This paper presents a survey on social networks' privacy leaks and the potential hazards for users, especially teenagers. In particular, the profiles of two teenagers, one male and one female, with fake names were created. Using a suitable software tool, friend requests were sent massively. As a result, two networks of friends were created and access was granted to a significant amount of users' personal information. Both profiles received requests for friendship and personal chat by adults aged up to 53 years old. In general the survey leads to results that reveal several hazards for children and critical issues about privacy of social network users.