Its use centers around a form of an advertising network , in which it gathers information about which users visit what websites .
The like button is one of Facebook 's social plug - ins , in which the button can be placed on third - party websites .
Facebook 's use centers around a form of an advertising network , in which it gathers information about which users visit what websites .
The like button is one of Facebook 's social plug - ins , in which the button can be placed on third - party websites .