Once information is posted to a social networking site, it is no longer private. The more information you post, the more vulnerable you may become. Even when using high security settings, friends or websites may inadvertently leak your information.
Personal information you share could be used to conduct attacks against you or your associates. The more information shared, the more likely someone could impersonate you and trick one of your friends into sharing personal information, downloading malware, or providing access to restricted sites.
Predators, hackers, business competitors, and foreign state actors troll social networking sites looking for information or people to target for exploitation.
Information gleaned from social networking sites may be used to design a specific attack that does not come by way of the social networking site.