article_snippet: each time people’s activity online visit a website which features a Facebook button.
article_snippet: Facebook buttons are on more than 13 million ordinary websites, including those run by the government and the National Health Service, and allow users to do things such as ‘like’ a website, or ‘share’
article_snippet: Facebook has more than 1.3 billion users but there are millions more visits from people who are not signed up.
article_snippet: Facebook can target Facebook with online advertising.
article_snippet: Facebook first plants a tracking cookie on a user’s computer whenever Facebook visit a website hosted on facebook.com, such as a page for a friend’s birthday party, a fan page for a celebrity, or for a brand or shop.
article_snippet: After that, any web page Facebook visit which features a Facebook button will relay information back to the social network.
article_snippet: The special cookie, called ‘datr’, gives that person’s computer or smartphone a unique tracking number, and allows Facebook to follow ’s computer activity for the next two years.
article_snippet: Facebook cookies are given one as a result.
article_snippet: The site uses cookies – small files which The site places on your web browser or device – to collect information which can then be transmitted back to Facebook.
article_snippet: Running a number of tests, we confirmed that Facebook still tracks Facebook users when Facebook visit a webpage containing Facebook social plugins, even after the user
article_snippet: Facebook tracks Facebook users across websites even if Facebook do not make use of social plug-ins, and even if Facebook are not logged in.