To be fair on Facebook, it is only making this data available to the apps if you, the user, specifically approve it. Moreover all those apps you have already installed won’t have automatic access to these information. So, next time you install a Facebook app, look out for the “Access my contact information: Current Address and Mobile Phone Number” permission request.
Facebook’s obnoxiously huge valuation is because of the data – the personal data of millions of users, all fed manually by the users themselves. And there is a huge demand for this data out in the market. If some app developer is greedy enough, he might sell your contact information to unwanted marketing mailing lists. Of-course Facebook mandates app developers to only request data they need to operate their apps, not to sell data on to third parties and to display a clear privacy policy. But how often and effectively they control is not well known. In a nutshell, it has become more important than ever to read the fine print before permitting an app to access your Facebook data. If it is looking for your contact information, think and re-think if it is a genuine app and worthy enough to be fed with personal info such as contact address and phone number.
