A US privacy group has written to Zuckerberg after his company announced on November 21 that it would end user-voting on privacy policies, and allow the sharing of information across its services.
The changes, which have generated more than 18,000 comments, also involve new settings giving users less control over who can contact them through the Facebook email system.
The Electronic Privacy Information Centre (Epic) said that the proposed changes "raise privacy risks for users", and may also violate a deal Facebook agreed with US regulator, the Federal Trade Commission (FTC).
Epic said that the voting system, introduced in 2009, was part of the now 1 billion member-strong social network's demonstration that it is committed to "an open and transparent system of governance".
The system worked by Facebook creating a blog post on a proposed change, and then allowing 30 days for user comments. If 7,000 users commented on the post, then the proposed change would go to a user vote. If fewer than 7,000 commented, then it would go through.
However, Facebook has argued that the voting mechanism created a system that "incentivised quantity of comments over the quality of them", and so it is scrapping the measure "in order to promote a more meaningful environment for feedback".
In April this year, Facebook reached a settlement with the FTC over claims that it had deceived its users over the use of their private information.
Facebook agreed to obtain users' consent for certain privacy setting changes, as well as submit to 20 years of independent audits.
But Epic feels that the most recent changes could be in violation of that deal.
On the email controls, Epic's letter said: "By removing users' ability to prevent strangers from sending unwanted messages, the proposed changes are likely to increase the amount of spam that users receive."
Epic also expressed concern over Facebook's proposal to allow 'Affiliates' to share information on the network, something that has been widely viewed as referring to Instagram, the photo-sharing app that was acquired by Facebook this year.
"When Facebook first announced its acquisition of Instagram, it also announced its commitment 'to building and growing Instagram independently', rather than integrating the two sites," said Epic.
"With the addition of the 'Affiliates' section however, Facebook could alter its practice of maintaining Instagram and Facebook user information separately. It could combine user profiles and freely share user data between the two sites."
Epic made the comparison to Google, which has been widely criticised for the consolidation of its privacy policies that means user information is shared automatically across multiple Google products, such as Google+, Gmail and YouTube.
In closing the letter to Zuckerberg, Epic said: "Facebook has been receptive to its users in the past. In 2010, you unveiled a set of simplified privacy controls in response to public criticism," the letter said.
"And in 2009, you agreed to back off proposed changes to the Terms of Service and establish the procedures for user input.
Now, we ask that Facebook be similarly responsive to the rights of Facebook users to control their personal information and to participate in the governance of Facebook.
"We ask that you withdraw the proposed changes to the Data Use Policy and the Statement of Rights and Responsibilities."
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