The social media giant Facebook has announced that it is to change its algorithm that decides what content to show in users' news feeds. The change is expected to roll out worldwide over the next few weeks and will decrease the prominence of posts by brands, businesses and media companies. Instead, greater visibility will be given to posts published by users' friends. The change is expected to have a large negative impact on businesses, especially media publishers who currently get a lot of their traffic from Facebook. Facebook said that posts by businesses will be given greater prominence only if they generate high levels of engagement. The social network hopes that this will encourage legitimate brands to create higher quality content, whilst making it more difficult for dubious brands to spread false information.