The hacker Nik Cubrilovic has revealed that Facebook collects data from users who have logged out. Facebook confirmed but insisted the information is only used for security purposes, aggregate statistics or it it not logged at all, the Wall Street Journal reports.
Facebook data collection works by storing small files called “cookies” on your computer when you visit their site. Some cookies linger after you log out. The cookies relay information from any site you visit that contains a link to Facebook such as a “like” button back to Facebook. With this data, Facebook can map out your web usage.
Arturo Bejar, the director of engineering for Facebook explained that the data is used to combat spam and phishing attacks by detecting suspicious logins. Also, cookies can use the data to keep users from having to complete extra authentication steps every time they log in. However, customers expect that “logging out” means that communication with the site is broken.
Public pressure has since stopped the company from seeking browsing data from non-Facebook users. And in 2011, it was revealed that Facebook continued to collect browser data from computers that had been turned off and from closed browsers, if the user had not logged out.