Mark Zuckerberg's latest Facebook post has proved a costly one.

The Facebook co-founder and CEO saw his fortune fall US$2.9 billion ($3.99b) after a post yesterday announcing changes to the platform's centerpiece news feed.

Zuckerberg said users' news feeds would focus on content created by family and friends at the expense of material from media outlets and businesses, according to Bloomberg.

Facebook shares tumbled 3.9 per cent in New York, cutting Zuckerberg's wealth to US$74.4b ($102.4b) on the Bloomberg Billionaires Index.

For much of the past few months, Zuckerberg has been thinking aloud about Facebook's mission, saying he wanted Facebook to become a place for meaningful social interaction. His resolution for 2018 was to "fix" Facebook, according to the South China Morning Post.

Zuckerberg said in the post yesterday that he wanted change the way Facebook ranks posts by putting more weight on social interactions and relationships.

While Facebook's advertising would be unaffected by the changes, the shift was likely to mean that the time people spend on Facebook and some measures of engagement would go down in the short term, Facebook said.

It may also have an impact on major suppliers of news and other content.

John Ridding, the chief executive of the Financial Times, warned on Friday that the domination of online advertising revenue by search and social media platforms was putting pressure on media firms.

"The FT welcomes moves to recognise and support trusted and reliable news and analysis. But a sustainable solution to the challenges of the new information ecosystem requires further measures," he said.

"In particular, a viable subscription model on platforms that enables publishers to build a direct relationship with readers and to manage the terms of access to their content."

The Daily Mail writes, Facebook has already started changing the way it filters posts and videos on its centerpiece news feed to prioritise content from friends and family of the user.

For example, a family video clip posted by a spouse will be deemed more worthy of attention than a snippet from a star or favorite restaurant.

But experts claim this is just another money-making scheme for the site, pushing companies to buy more adverts to get user attention.

"As we roll this out, you'll see less public content like posts from businesses, brands, and media," Zuckerberg said in a post at his Facebook page.

"And the public content you see more will be held to the same standard - it should encourage meaningful interactions between people."

The company has for years prioritised material that its complex computer algorithms think people will engage with through comments, 'likes' or other ways of showing interest.

Zuckerberg said that would no longer be the goal.

"I'm changing the goal I give our product teams from focusing on helping you find relevant content to helping you have more meaningful social interactions," Zuckerberg said.

Zuckerberg said it would be better for users and for the business over the long term.

Facebook and its social media competitors have been inundated by criticism that their products reinforce users' views on social and political issues and lead to addictive viewing habits, raising questions about possible regulation and the businesses' long-term viability.

With more than 2 billion monthly users, Facebook is the world's largest social media network.