Recently Facebook enhanced its privacy controls on the information. Users are supposed to be able to control who can access personal data for instance personal pictures. Nevertheless, a hole in security allowed to access personal pictures independently from their control rules. Journalist from Associated Press (AP) was able to browse among personal pictures (see AP news) Facebook quickly fixed the hole.

Once more, this news rises the question about privacy and social networks. Social networks are not different from traditional web sites. Data stored on their server are vulnerable and may be exposed. Social networks, due to their social role, increase the problem. Information posted on these networks are by nature personal thus potentially sensitive.

Data on social networks (or any other type of sites) have two characteristics:

• They are vulnerable. They may leak or may be stolen
• They are persistent. Internet has a huge memory. Ten years old data are still somewhere in the cyberspace, available to revealed.

The consequences are:

• Information that you do not want to be public may become public
• Information that were not important today may become embarrassing in the future. These information will be available and may ruin reputation.

Thus, a rule: Do never post a personal information that you do not want to become one day public It may become public.