But it's not the kind of special treatment that comes from owning the site, at least directly. Instead, it what happens when people don't want to see your posts so much that they'll block you.

The pair can't be blocked on Facebook, and trying to do so will just lead to error messages from the site. And that seems to be a result of the fact that they have been blocked so many times that the site is stopping it happening.

How to stop Facebook from revealing everything about you Show all 9 1 /9 How to stop Facebook from revealing everything about you How to stop Facebook from revealing everything about you Lock your profile down If you haven’t done this already, do it now. In Settings, hit the Privacy tab. From here, you can control who gets to see your future posts and friends list. Choose from Public, Friends, Only Me and Custom in the dropdown menu. How to stop Facebook from revealing everything about you Limit old posts Annoyingly, changing this has no effect on who’s able to see your past Facebook posts. Instead, on the Privacy page, you have to click on Limit Past Posts, then select Limit Old Posts and finally hit Confirm on the pop-up. How to stop Facebook from revealing everything about you Make yourself harder to find You can stop completely random people from adding you by selecting Friends of Friends from the dropdown menu in the Who can send you friend requests? section of the Privacy page. It’s also worth limiting who can find your Facebook profile with your number and email address. At the bottom of the page is the option to prevent search engines outside of Facebook from linking to your profile. How to stop Facebook from revealing everything about you Control access to your Timeline You can limit who gets to post things on your Timeline and who gets to see posts on your Timeline too. In Settings, go to Timeline and Tagging and edit the sections you want to lock down. How to stop Facebook from revealing everything about you Block people When you block someone, they won’t be able to see things you post on your Timeline, tag you, invite you to events or groups, start conversations with you or add you as a friend. To do it, go to Settings and Blocking. Annoyingly, you have to block people on Messenger separately. You can also add friends to your Restricted list here, which means they’ll still be friends with you but will only be able to see your public posts and things you share on a mutual friend's Timeline. How to stop Facebook from revealing everything about you Review tags One of Facebook’s handiest privacy features is the ability to review posts you’re tagged in before they appear on your Timeline. They’ll still be visible on the News Feed while they’re fresh, but won’t be tied to your profile forever. In Timeline and Tagging, enable Timeline review controls. How to stop Facebook from revealing everything about you Clean up your apps You can view a list of all of the apps you’ve connected to your Facebook account by going to Settings and Apps. The list might be longer than you expected it to be. It’s worth tidying this up to ensure things you no longer use lose access to your personal information. If you don’t want to log into websites and apps with your facebook account, scroll down and turn Platform off. How to stop Facebook from revealing everything about you Change your ad preferences You can view a list of everything Facebook thinks you’re into and tinker with your ad preferences by going to Settings and Adverts. A lot more information is displayed on the desktop site than the app, so we’d recommend doing this on a computer. How to stop Facebook from revealing everything about you Download your data Facebook lets you download all of the data it has on you, including the posts you’ve shared, your messages and photos, ads you’ve clicked on and even the IP addresses that are logged when you log in or out of the site. It’s a hell of a lot of information, which you should download to ensure you never over-share on the social network again.

You can press the block button on both of their profiles, and Facebook will check you know what you're doing. But then you'll be hit by a big box reading "Block Error", which explains that there "was a problem while blocking Mark Zuckerberg" – or Priscilla Chan – and they should "please try again".

But trying won't help. It's not possible to block either person, because Facebook has decided to stop it.

It's especially noticeable because Mr Zuckerberg tends to post on his personal page about updates to Facebook, news about his personal life, or statements on current events. Those posts then seem to benefit from help from the Facebook algorithm and are interacted with, pushing them onto people's news feeds.

Blocking the Facebook founder and his wife was a useful way of keeping those posts from appearing, before it was banned. That ban has been in place for some years – since at least 2010 – and even led to a now-defunct website that exists only to point out that it's impossible to block Mr Zuckerberg.

But the company has said that they aren't receiving any special treatment, and their posts are simply so disliked that it triggered automated systems. The site can only allow a person to be blocked a certain number of times, and once that limit is reached they can be blocked no more.

"This error isn't specific to any one account," a Facebook spokesperson told Gizmodo. "It's generated when a person has been blocked a certain large number of times. In very rare instances, a viral campaign will develop instructing lots of people to all wrongly block the same person.