Facebook has announced the latest tweak to its news feed algorithm, and it's bad news for needy influencers and brands operating on the social network.

The company is cracking down on 'engagement bait': posts that explicitly ask people to interact with them by liking, sharing and commenting.

"For example, 'LIKE this if you’re an Aries!' This tactic, known as 'engagement bait,' seeks to take advantage of our news feed algorithm by boosting engagement in order to get greater reach," explained Facebook in a blog post. "Starting this week, we will begin demoting individual posts from people and pages that use engagement bait."

Facebook has been training a machine-learning algorithm to identify likely engagement bait, to help weed these posts out of people's news feeds. And there's more bad news for anyone that continues using the tactic for their page posts.

"Over the coming weeks, we will begin implementing stricter demotions for pages that systematically and repeatedly use engagement bait to artificially gain reach in news feed," it explained, adding that this will not kick in immediately, to give publishers and influencers time to adapt.

Facebook also stressed that it won't be demoting posts or pages that are asking for help, advice or recommendations: "such as circulating a missing child report, raising money for a cause, or asking for travel tips".