Privacy and sharing don't have to be at odds, according to Facebook CEO Mark Zuckerberg. (AP Photo/Jeff Chiu)

Chief executive Mark Zuckerberg once famously said that privacy was no longer a "social norm" in a society that seemed compelled to share everything. But recent moves from Facebook signal that Zuckerberg might be changing his mind about what privacy means in a modern age -- or at least how Facebook can advertise its privacy standards to put users' minds at ease.

Facebook, it's safe to say, has always had a tricky relationship with privacy. After all, the whole point of the social network is to share information--and the more data on users, the better for Facebook's business. The problem, however, is that the company hasn't always seemed to understand what users do and don't want to share with particular people, or the whole world. That's dropped it into some major privacy dust-ups over the years, including complaints that led to a settlement with the Federal Trade Commission over its privacy policies in 2011. More recently, the company upset users after researchers published a paper on a mood manipulation study of its users.

The heat is still on. Starting in June, Facebook began collecting  information from across the Web, rather than just within its network, to determine what kind of ads it should show users. Nearly all companies that rely on online advertising do this. But privacy advocates from the Trans Atlantic Consumer Dialogue -- a collection of consumer groups from the U.S. and Europe that focus on a number of social policy issues, including information policy -- have argued that this dramatically increases the amount of data Facebook holds and that users were not properly notified about the change.

On Tuesday, U.S. and European privacy advocates sent a letter to the Federal Trade Commission and the Irish Data Protection Commission, which has oversight over Facebook's operations in Europe. The advocates said recent Facebook ad policy changes must be examined to make sure they comply with U.S. and European law.

Facebook did not immediately respond to a request for comment. But the company has lately been trying to win trust from users by revamping what it shows users about their privacy options.

For instance, when the company broadened its ad network in June, it also redesigned the settings for the ads shows on its news feed that explicitly explained why they were seeing certain ads, based on things they'd liked or pages they follow. In April, there was another big push to better acquaint users with their privacy settings and make some settings more obvious.

Also in April, Facebook made yet another change allowing users to log in to outside apps such a Spotify or Flipboard without having to also share personal information from their network profiles.

In the firm's most recent earnings call, Brian Pitz, an analyst at Jefferies, asked Zuckerberg to explain what Pitz viewed as the social network's "strategic shift" in the way it views privacy.

Zuckerberg's reply revealed his unique view of privacy -- one that's not concerned primarily between what users share with companies but with what users share with one another.

Facebook's founder said that the company's views on privacy are evolving as the Internet itself does and argued that, in a way, Facebook has always had the question of what's private and what's public at its core.

When Facebook first came onto the scene over a decade ago, he said, people pretty much had the option to either post their thoughts publicly in blogs or privately in e-mail -- with no middle ground. Facebook was designed to slot into the middle, said Zuckerberg.

"There is just a lot more that people want to express and that they need the tools to express with smaller groups of people, not just one person at a time but smaller groups as well," he said on the call.

This strategy is playing out in a few ways, most notably with Facebook's recent plan to break out its functions into several apps to serve particular, often more personal functions. Starting this week, anyone who wants to chat on Facebook must use Messenger, a standalone app. That breakout could serve as a sort of mental wall for Facebook users -- even if Messenger users are still sending information such as their location back to Facebook.

But within the confines of a separate app, users may feel more at ease, argues Zuckerberg. He said specifically that messaging "opens up new different private spaces for people where they can then feel comfortable sharing and having the freedom to express something you otherwise wouldn't be able to."

However Facebook decides to articulate its vision of privacy, there's still one fundamental fact: the company is raking in hundreds of millions of dollars selling ads based on the user data it's harvesting. And regardless of how uncomfortable some users may be with what Facebook does with the data, they don't show any signs of slowing how much they share.