On Wednesday, Facebook CEO Mark Zuckerberg published a more-than-3,000-word blog post that seems to declare a major shift in Facebook's strategy. In it, he says he believes that "a privacy-focused communications platform will become even more important than today's open platforms."

Zuckerberg explains that he wants Facebook to build a privacy-focused messaging and social networking platform, and describes his vision thusly:

Public social networks will continue to be very important in people's lives—for connecting with everyone you know, discovering new people, ideas and content, and giving people a voice more broadly. People find these valuable every day, and there are still a lot of useful services to build on top of them. But now, with all the ways people also want to interact privately, there's also an opportunity to build a simpler platform that's focused on privacy first.

He acknowledges Facebook is an odd fit for this approach, saying, "frankly we don't currently have a strong reputation for building privacy protective services, and we've historically focused on tools for more open sharing," but:

I believe the future of communication will increasingly shift to private, encrypted services where people can be confident what they say to each other stays secure and their messages and content won't stick around forever. This is the future I hope we will help bring about.

He adds that this will be built around the following principles:

Private Interactions

Encryption

Reducing permanence

Safety

Interoperability

Secure data storage

As far as private interactions go, he simply means he sees users increasingly utilizing group and direct messaging rather than or in addition to publishing content to all of their friends or followers.

Zuckerberg positions this and the need for a focus on privacy as realizations he has come to, but they're things budding competitors to various Facebook products and businesses have already been focusing on for years.

End-to-end encryption across the Facebook network

He also announces intentions to make all these communications encrypted end-to-end (this is already the case with WhatsApp). "In a few years, I expect future versions of Messenger and WhatsApp to become the main ways people communicate on the Facebook network," he explains. "We're focused on making both of these apps faster, simpler, more private and more secure, including with end-to-end encryption."

He talks up the benefits of this approach for security and privacy but admits that it will pose challenges for ensuring users' safety in other ways:

When billions of people use a service to connect, some of them are going to misuse it for truly terrible things like child exploitation, terrorism, and extortion. We have a responsibility to work with law enforcement and to help prevent these wherever we can. We are working to improve our ability to identify and stop bad actors across our apps by detecting patterns of activity or through other means, even when we can't see the content of the messages, and we will continue to invest in this work.

“Reducing permanence”

Facebook has come under considerable fire over the past few years for its failure or inability (depending on who you ask) to crack down on false or abusive content shared by its users. While the benefits of encryption are real and significant, Zuckerberg and Facebook may be thinking of another upside. When encryption precludes access to the content of users’ messages, Facebook might face lower expectations of responsibility for protecting users from those problems, since enforcement of any policies will be nigh impossible in many cases.

Encryption is not the only way to protect users data, Zuckerberg argues. Snapchat-like impermanence of messages is also part of his plan.

Messages could be deleted after a month or a year by default. This would reduce the risk of your messages resurfacing and embarrassing you later. Of course you'd have the ability to change the timeframe or turn off auto-deletion for your threads if you wanted. And we could also provide an option for you to set individual messages to expire after a few seconds or minutes if you wanted.

He adds that the company will limit the amount of time it stores messaging metadata. Along with the other changes, he positions this as an effort to protect users' data from overreaching governments.

Merging WhatsApp, Instagram, and Messenger

Zuckerberg additionally announces that the company will integrate WhatsApp, Instagram, and Messenger into one messaging system, allowing users to seamlessly send and receive messages between them.

"People want to be able to choose which service they use to communicate with people," Zuckerberg says, but "if you want to message people on Facebook you have to use Messenger, on Instagram you have to use Direct, and on WhatsApp you have to use WhatsApp."

In the new approach, users will be able to send messages to their friends using any of Facebook's messaging apps, regardless of which ones those friends are using. Facebook has said in the past that it would not merge WhatsApp data with the rest of Facebook, but Facebook will break this promise by making the three apps share the same back end, according to The New York Times' sources. The three messaging platforms together have about 2.6 billion users. Facebook hopes to complete this transition by early 2020.

Zuckerberg says that interoperability will extend to SMS. This is already possible with the Messenger app on Android, but Facebook will extend that using the RCS standard. However, this feature will likely never be possible on iPhones, as Apple "doesn't allow apps to interoperate with SMS on their devices."

While these changes will result in greater convenience for users, they will also create a value proposition with which it will be very difficult for other platforms to compete. Another challenge the blog post identifies: this new system "would create safety and spam vulnerabilities in an encrypted system to let people send messages from unknown apps where our safety and security systems couldn't see the patterns of activity."

Zuckerberg doesn't name a solution for this, but says it is something Facebook will be working through.

Storing user data away from government overreach

Continuing the theme of user privacy and security, Zuckerberg says it will avoid storing user data in data centers that are in countries where that data might be compromised by local governments—even if it means Facebook won't be able to expand in places where it would like to.

As we build our infrastructure around the world, we've chosen not to build data centers in countries that have a track record of violating human rights like privacy or freedom of expression. If we build data centers and store sensitive data in these countries, rather than just caching non-sensitive data, it could make it easier for those governments to take people's information. Upholding this principle may mean that our services will get blocked in some countries, or that we won't be able to enter others anytime soon. That's a tradeoff we're willing to make. We do not believe storing people's data in some countries is a secure enough foundation to build such important internet infrastructure on.

This could pose problems for expansion in China, a place that Facebook executives have previously named as a region with growth potential.

The future of Facebook is more uncertain than ever

While some changes like end-to-end encryption are meant to ease users' and regulators' fears about privacy, other parts of this vision will likely stoke new resentments and criticisms. Merging the three messaging apps will make mobile messaging a less competitive market. And The New York Times reports that the decision to integrate WhatsApp into the wider system has been seen as a betrayal internally, and that WhatsApp employees and executives have begun departing in protest.

Facebook acquired WhatsApp for $19 billion in 2014, with a promise of independence and a different standard for privacy than users of Facebook's core social network see. The decision to acquire WhatsApp was informed by data Facebook harvested from its users about their usage of other smartphone apps besides Facebook, against smartphone platforms’ terms

And there's one key thing that wasn't discussed: how Facebook’s existing business model of data collection and advertising based on that data will work with this approach moving forward. Zuckerberg did note that this new approach to messages presents new business opportunities related to payments and other “private services," and though he doesn't specify this, it's clear that giving the advertisers the ability to reach users across all three messaging platforms could prove lucrative.

But given that Facebook’s current revenue model depends on vast databases of publicly shared information, there are many questions to ask. And this transition will likely take a long time to make. But Zuckerberg may see writing on the wall here: young people are using private messaging apps more than older people, and users, the press, and government officials are daily and loudly challenging and criticizing the company’s privacy practices and the foundations of its existing business model.

Zuckerberg has announced privacy initiatives in the past, but then not delivered on them. This lengthy blog post guarantees nothing but the start of a new phase of the conversation. Tellingly, Facebook stock didn't budge on news of Zuckerberg's post. Investors may be waiting to see just how serious he really is—and so, too, are users and regulators.