Facebook users fall into two camps – those who play the games and those who hate them. Personally I’m in the latter camp: a total of 18 applications are blocked from contacting me for information and more than 70 cannot even make it to my News Feed.
But now there is evidence that building farms or whatever else those things do can be harmful. The Wall Street Journal has found that many Facebook applications can pass on information that personally identifies users and their friends to advertisers.
Here’s how it works.
The applications can grab your Facebook user ID number, which is unique to you. This is then sold on to an advertiser. It is then used to look up your name and other personal information – even if your profile is set at its strictest setting. It also reveals any data that has been set to be visible to “everyone” on the site, which in fact means visible across the web.
And three of the top 10 apps, including FarmVille, can also transmit personal information about your friends to external companies.
The Wall Street Journal said that the apps were sending Facebook IDs to at least 25 advertising and data firms, which build profiles of people by tracking them online.
Collecting user and friends’ IDs allows companies to build up individual profiles, which it can then cross-match with other data collected from censuses and public information to create detailed profiles of people. While advertisers argue that that means better-targeted information, there are obvious privacy concerns here.
Facebook has reminded users that the apps are developed by third party companies rather than by the company itself. But it has said that it is moving to “dramatically limit” the leaking of users’ personal information, as it breaks the site’s own rules.
So the next time you see a request on Facebook asking you to join a friend’s Mafia gang or help them out by selling chickens, think twice before you get involved.