For 15 years, Facebook has pushed, prodded, cajoled, lured and tricked billions of people into sharing the most intimate details of their lives online, all purportedly in service of making the world “more open and connected”.

On Wednesday, the company’s CEO Mark Zuckerberg put forward a new idea: doing the opposite.

“As I think about the future of the internet, I believe a privacy-focused communications platform will become even more important than today’s open platforms,” he wrote in a blogpost announcing his new “vision” for social networking.

Facebook and Instagram are “the digital equivalent of a town square”, he wrote, but people increasingly want to spend time in “the digital equivalent of the living room”.

“Privacy gives people the freedom to be themselves and connect more naturally, which is why we build social networks.”

The brass tacks of Zuckerberg’s announcement relate not to Facebook’s core feature – the news feed – but to a previously disclosed plan to integrate the messaging services of its three apps: WhatsApp, Messenger and Instagram.

This new messaging service will be built with privacy in mind, Zuckerberg said, with a focus on features such as end-to-end encryption and ephemerality, ie automatically deleting messages after a certain period of time.

Critics of the company greeted Zuckerberg’s suggestion that the product update is about privacy with instant skepticism. Facebook’s reputation has been shredded by years of scandal over issues ranging from data misuse and data breaches to the hijacking of democratic elections and fueling of hate and violence.

“I strongly support consumer privacy when communicating online but this move is entirely a strategic play to use privacy as a competitive advantage & further lock-in Facebook as the dominant messaging platform,” tweeted Ashkan Soltani, a former chief technologist for the Federal Trade Commission. “While positioned as a privacy-friendly play, its timing suggests a competition play to head off any potential regulatory efforts to limit data sharing across services.”

Jonathan Albright, the director of the digital forensics initiative at the Tow Center for Digital Journalism, warned against conflating the increased “platform security” that comes with end-to-end encryption with “user-focused privacy improvements”.

“Privacy is really about the citizens’ right to control what is shared, and know the contexts in how it can be accessed,” he said. “Nothing has changed in terms of that control. Access to users’ data is still dictated by Facebook. And now the terms of service will expand to all of Facebook’s subordinate services and apps.”

Zuckerberg showed himself to at least be aware of the challenge Facebook will face to be taken seriously by privacy experts.

“I understand that many people don’t think Facebook can or would even want to build this kind of privacy-focused platform – because 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,” he wrote. “But we’ve repeatedly shown that we can evolve to build the services that people really want, including in private messaging and stories.”

There has long been a disconnect between how Facebook defines privacy and how advocates do. Facebook has generally focused on limiting the amount of information that the public or a government can access about an individual, while privacy experts have pushed for the platform to limit the amount of information that it collects and retains about its users.

Implementing end-to-end encryption will prevent Facebook from collecting data on the content of its users’ messages, but Facebook has not said that it will change or limit its collection of data about users on other fronts. Its business model is dependent on leveraging its incredibly voluminous and detailed information about users to sell advertising.

In the blogpost, Zuckerberg also described a commitment not to store people’s data in “countries that have a track record of violating human rights like privacy or freedom of expression”, noting the potential for government abuse.

“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,” he wrote. “That’s a tradeoff we’re willing to make.”

Zuckerberg has long sought to enter the Chinese market, without success.