Facebook CEO Mark Zuckerberg on Wednesday made a major proclamation: The future of Facebook is one focused on private communication.

Zuckerberg's new stance was delivered in a 3,000-word note titled "A Privacy-Focused Vision for Social Networking." The note outlines the framework with which the company will integrate the private messaging features of its Messenger, Instagram and WhatsApp apps, and it comes after a grueling 2018 in which the company was plagued by multiple scandals related to user privacy.

"I believe we should be working towards a world where people can speak privately and live freely knowing that their information will only be seen by who they want to see it and won't all stick around forever," Zuckerberg wrote.

It's a nice vision, but if history is any indicator, there's no reason to believe Zuckerberg.

Zuckerberg has done his best to emulate Steve Jobs through his penmanship in notes like the one we saw this week or his showmanship on stage at events like the company's annual F8 conference, yet his company's actions rarely deliver on his words. And there are plenty of examples of this.

When it comes to privacy, there are numerous examples throughout Facebook's history where Zuckerberg has made bold claims about Facebook privacy only to be proven wrong over and over.

But it's not just privacy issues. There are plenty of other examples where Zuckerberg has promised bold new products — like he did in his essay Wednesday — and failed to deliver.

The first time Zuckerberg hyped a Facebook announcement only to let everyone down over a long period of waiting was back in 2013. Zuckerberg got up before a crowd of journalists to announce "graph search." This was supposed to be a new breakthrough in search engines. It was a search engine you could ask hyper-specific questions to and receive personalized results. You could ask it questions like "music listened to by my friends who listen to Beyonce" or "my friends who live in Houston" and get exactly what you asked for. That's what Zuckerberg promised, but it never came to be. Just try to ask Facebook's search these questions. Search has improved since this announcement, but the results are not what he promised.

Something similar happened later in 2013 when the company announced Facebook Home, a custom version of Android that would launch on the HTC First smartphone. Zuckerberg got on stage to announce both products to much fanfare. This was Facebook's grand entry into the mobile market. Instead, the phone and the software were instant flops, and Facebook didn't take long to abandon the project, with AT&T slashing the price of the HTC First from $99 to just 99 cents within weeks of its launch.

In more recent years, Zuckerberg's words have rung hollow when it comes to his promises for improving the way people talk and connect on the service.

If you thought Zuckerberg's note this week was long, just look at the mammoth manifesto he wrote in 2017. In that 6,000-word essay, Zuckerberg made multiple promises about improving Facebook after the company came under fire for its failure to address fake news ahead of the 2016 U.S. election. In that note, Zuckerberg made one particular promises that stands out.

He wrote about using artificial intelligence to keep Facebook a community free from bullying and harassment. This promise has failed on two counts. For starters, Facebook is still littered with issues of bullying and harassment, and it's especially a problem for younger users on Instagram. Secondly, Facebook is not yet at a point where it can rely on AI to remove content that shouldn't be allowed on the service. The company uses AI for much of its content moderation, but it still relies on thousands of low-paid contractors working in subpar conditions and exposing themselves to content that scars them, as Casey Newton of The Verge demonstrated in his excellent profile of Facebook's content moderators.

And then there was Zuckerberg's News Feed algorithm change of 2018. At the time, Zuckerberg announced that Facebook would make "a major change" to how Facebook was built so that the company prioritized "meaningful social interactions" over "relevant content." In layman's terms, this meant showing users more content about their friends and less content from publishers. The change certainly had a major impact — just look at the recent layoffs at digital news outlets like Mic and BuzzFeed, two publishers whose business models had relied on traffic from Facebook. And yet, does it really feel like News Feed has improved or been filled with meaningful social interactions? Mine certainly hasn't. One quick look at my feed and my top posts are a news article, an ad, a news article, a news article and some "friend" I can't remember who changed his profile picture.

At least year's F8 conference, Zuckerberg took the stage and promised the company would release a feature called Clear History that would give users more control over the data Facebook has on them. The feature was thought up just prior to F8, according to a BuzzFeed report, and nearly one year later, it has yet to be released. The company said recently that Clear History will arrive sometime in 2019, but no set date has been given.

This is why I don't expect much from Zuckerberg's latest promise. The note itself is laced with caveats that should temper expectations. For starters, Zuckerberg says this more private version of Facebook is a work in process that will take a few years to come to fruition. And Zuckerberg himself addresses doubt in his note.

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. But we've repeatedly shown that we can evolve to build the services that people really want, including in private messaging and stories.

And although Facebook may be expanding its focus on private communication, the company has no plans to get rid of its existing public products like News Feed and Instagram, according to an interview Zuckerberg gave to Wired.

Asked in that interview what he will do to guarantee this privacy-focused vision is carried out, Zuckerberg sidestepped the question and gave no guarantees.

Here's what he said:

You have no idea how hard it is. Yes, there's a lot of work that goes into getting the teams aligned and getting the right leaders in place who believe in these priorities, and being able to execute on that. And even the process of writing something like this is really helpful, because you can talk about a lot of things in the abstract. But it's not until you actually put it down on paper and say, "Yeah, here are the trade-offs. We're going to focus on reducing the permanence of how much data we have around, and that's going to make these things harder." Then you get all these teams inside the company that come out of the woodwork with all the issues that that's going to cause for other things that we really care about. You know, whether that's research that was surfaced about how much people care and value making a record of their lives over time, so making it so that more of the content would be archived automatically would be problematic for them, or different kinds of things. But that whole process has been really helpful for figuring out and distilling the vision of where we want to get. And it basically got us to this point where we feel like we're ready to put a flag in the ground and say, "This is where we want to go." This isn't a product announcement, it's a statement of the principles that we think are necessary to build this privacy-focused social platform. But now I think we're going to really start the harder process, over the next year or so, of flushing out what all these things mean as the aspects of this start to get rolled out in the different products.

Perhaps this will be the time Zuckerberg finally delivers on a promise, but don't get your hopes up.

WATCH: Here's how to see which apps have access to your Facebook data — and cut them off