In general - of course we are. However, there is a large portion of society that is also very "social-network aware". This means that they are aware of the ramifications of sharing too much personal information on websites such as Facebook or Instagram.
What is interesting about this is that these same people may not have been aware had those who came before them not caused problems for themselves by sharing too much. It was the people who ended up losing their privacy, or finding themselves victims of certain cyber-crimes who became newsworthy. These people ended up putting themselves out there for the benefit of others. Because of their mistakes we now know how dangerous it can be to "over share".
Furthermore, even though many people do not over share, there are many people that still do. From the young to the nieve. They continue to share their personal information or "give" too much and will continue to end up the victims. As they do society in general will make the assumption that "we" all share too much and questions like this will continue to be asked.