Users' adresses and mobile numbers to be made available to apps people use on site – if explicit permission granted

Facebook is planning to make users' addresses and mobile phone numbers available to apps that people use on the site, although it says it would require users to give explicit permission for it to happen.

The company reiterated its plan to go ahead with opening up users' personal details, which was first revealed in a blogpost on its Developer blog in January — opaquely entitled "Platform Updates: New User Object fields, Edge.remove Event and More" — but suspended three days later in the face of angry responses from privacy advocates.

That included a letter from US congress representatives Edward Markey and Joe Barton, who objected to the idea. "Facebook needs to protect the personal information of its users to ensure that Facebook doesn't become Phonebook," Markey wrote. "That's why I am requesting responses to these questions to better understand Facebook's practices regarding possible access to users' personal information by third parties. This is sensitive data and needs to be protected."

Despite criticism from privacy advocates and lawmakers in the US when the plans were announced, the company said in a letter to the House of Representatives by Marne Levine, its vice president of global public policy, published on Tuesday, that "We expect that, once the feature [to share address and mobile data] is re-enabled, Facebook will again permit users to authorise application to obtain their contact information." But Facebook is "currently evaluating methods to further enhance user control in this area".

The change will make the data available to app developers via a "permissions dialog" when users enable an app on the social networking site.

Writing at MSNBC, Helen Popkin said of the latest plan that "Facebook is the slowly-warming pot of water and we, my friends, are the frog. By the time we noticed our peeling skin, another hunk of our privacy is long gone."

She commented that Facebook's announcement, reversal, and re-announcement fits a repeated pattern: "This is how Facebook rolls: Strip away a huge chunk of your privacy, cry 'Our bad!' and roll it back when users and/or privacy advocates complain. Then wait awhile, and do whatever it is Facebook planned to do anyway. Voila! Boiled frog."

Facebook is meanwhile experimenting with a new privacy policy that would be more like a guide to how personal information is used, rather than a long legal document.