NEW YORK (CNNMoney) -- Facebook is giving app developers access to some of the most sensitive personal data it possess: Members' addresses and phone numbers.
The company slipped the change in quietly, announcing it late last week in a post on its developer blog.
Facebook members will need to explicitly grant permission for apps to tap into their contact information. And they'll only be able to grant that permission for their own data -- users can't choose to allow access to their friends' contact information.
But that may not be enough of a shield. Facebook frequently comes under fire for its constantly changing privacy policies, and many users find the tools it makes available for adjusting privacy settings very confusing.
Privacy researcher Christopher Soghoian thinks Facebook botched the message by publicizing the change on its the developer's blog.
"They should have had an announcement: 'This is why were doing this, and is why it's not a privacy problem,'" he says.
The blog Inside Facebook, which obsessively tracks news about the social networking giant, says the new addition doesn't provide users with enough context.
"The biggest problem with access to contact information is that the permission requests for these highly sensitive data fields are not distinguished from requests for more benign data like a user's Event RSVPs or privileges like publishing to their stream," Inside Facebook writer Josh Constine says.
Facebook CEO Mark Zuckerberg has been vocal about his view that information wants to be shared.
Last May, in the wake of multiple privacy flare-ups, he described his approach in a Facebook blog post.
"When we started Facebook, we built it around a few simple ideas. People want to share and stay connected with their friends and the people around them. When you have control over what you share, you want to share more," Zuckerberg wrote. "When you share more, the world becomes more open and connected."
Soghoian expects that many Facebook users will allow access to their contact information -- even if they're not thrilled about it.
"For much of the content out there, it's going to be compelling enough or social enough that you're not going to say no," he says. "Consumers don't negotiate with Facebook apps. It's 'take it or leave it.'"
For those that take it, how safe will the data be?
Facebook's terms of service prohibit app makers from transmitting the data they collect to outside parties, but those policies have been violated before. Facebook came under fire last year when San Francisco-based marketing company Rapleaf gathered Facebook IDs from apps and sold those IDs to advertisers.
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