Just read a news "Internet users may face more privacy threats as marketers aggressively collect information " which is a good post, I think we should read and know the threats then we will know how to deal with and protect us.
http://economictimes.indiatimes.com/tech/internet/internet-users-may-face-more-privacy-threats-as-marketers-aggressively-collect-information/articleshow/27934758.cms