"Facebook collects....(and) it records a user’s online usage patterns, including the browser they use,the user's IP address and how long they spend logged into the site." 

There is no excuse for not knowing the degree to which we are giving away our rights to privacy.  This article will outline the threats:  You Are Being Tracked Online: Here Are 5 Ways to Protect Your Privacy

They are not alone in doing this.  And neither are you, any more, ever. "Once you connect to the digital ether, whether via a computer, smartphone or tablet, your ostensible private information becomes public and prime for commercialization."

The Federal Trade Commission issued a warning earlier in February over apparent violations of children’s privacy rights involving the operating systems of the Apple iPhone and iPad as well as Google’s Android and their respective apps developers. Its report, "Mobile Apps for Kids," examined 8,000 mobile apps designed for children and found that parents couldn’t safeguard the personal information the app maker collected.