BERLIN–Facebook can use the “Like” button to collect information about the surfing behavior of its users. That is also the case if the button is connected to other pages. If you want to prevent that then you should log out from the social network while surfing, according to Holger Junker from the German Federal Office for Information Security. The data can only be attached as long as the user is logged on to Facebook while surfing. Other helpful means are browser plug-ins such as Facebook Blocker for Firefox and Safari and Facebook Disconnect for Google Chrome. Facebook is not the only one using this technique. “Many website operators use tools from other providers to collect information about their visitors,” said Junker. But usually it would only be an IP address that does not disclose too much information about the user. Those who surf while logged onto Facebook provide the operators of the social network with their surfing behaviour as well as personal information.