A guide to understanding social media algorithms in 2021

Understanding the various social media algorithms is a difficult task. In 2018 I took a look at everything you need to know about social media algorithms – here we see how the platforms have changed in 2021.

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Trying to understand the individual intricacies and nuances of each social media platform can be a very tricky task. However, it is something that you need to get your head around in order to make sure your social media strategy is as successful as possible. In 2018, I wrote our first guide to social media algorithms, and now almost three years on, let’s have a look at how they have changed.

Social media platforms are constantly evolving, making it difficult to stay on top of every single change and tweak to the algorithm. With that in mind, here are some of the most important things you should know about the top social media platforms and how their algorithms work.

How does Facebook’s algorithm work?

Since my last post on social media algorithms in 2018, organic reach on Facebook has seen a consistent decline each year. According to Hootsuite’s Global State of Digital 2021, the average reach for an organic Facebook post is 5.2%, down from 7.7% in 2018. This highlights the fact that Facebook’s algorithm can be quite difficult to understand, especially with organic branded content.

As was the case in 2018, Facebook does not display posts in chronological order, instead it arranges them in order of perceived interest for each user. While we don’t know the exact details of how it decides what posts to show you, we do know the goal is to keep you scrolling – that way they can show you more ads.

One thing we do know is that Facebook will use a range of ranking signals to determine whether or not to display a post in your newsfeed, and in what order to display these posts. It will then discard any posts that the user is unlikely to engage with and score the remaining posts in a personalised way. This is based on how you have engaged with similar posts in the past. All of these posts are then arranged to display a variety of media types from different sources to keep the user engaged and scrolling.

Although Facebook uses thousands of ranking signals such as how users engage with posts, or the speed of their internet, below are the four most important:

  • Relationship: Who shared the post? Was it from one of your friends or family, or was it a business or news outlet? In 2018 Facebook placed greater emphasis on posts from friends and family over businesses; something which remains true in 2021.
  • Content type: What type of posts do you engage with the most? Are photos or videos more likely to attract your attention?
  • Popularity: How are your friends reacting to this post? How your friends engage with a post, whether that is sharing, commenting, or reacting has an impact on whether a post will show in your feed.
  • Recency: The newer the post the higher it will be displayed in a user’s feed. Simple.

From a marketing perspective, there has been no massive change in how you should tackle Facebook. Considering the above ranking factors, it’s important to share regular posts that will spark a conversation with your followers or grab their attention. Furthermore, be sure to include a variety of content types as part of your social media strategy to keep your followers engaged.

How does Twitter’s algorithm work?

Twitter’s algorithm underwent a major overhaul in 2017, which I covered in my previous post, and the main changes that were added during this overhaul are still in place. Twitter’s algorithm splits the timeline into three main sections.

  • Ranked tweets – These appear at the top of the feed and display tweets that are deemed to be the most relevant.
  • “In case you missed it” – Again this appears toward the top of your feed and includes older posts that you may have previously missed.
  • Remaining tweets – The includes any other tweets that are not displayed in the above two sections.

Since my previous post in 2018, the Twitter algorithm hasn’t changed dramatically. Engagement is still vital for success, the more a post is engaged with the more likely it will appear in your followers ranked tweets or “In case you missed it”. Like with Facebook, try to share posts that will spark a reaction from your followers, find ways to question them to provoke a conversation. After all, conversations are at the core of what Twitter was created for.

How does Instagram’s algorithm work?

Unsurprisingly, Instagram’s algorithm and feed work in a very similar way to Facebook. Its algorithm will comb through all the available content and then decide which posts to display to its users. By doing this the algorithm will determine which posts are displayed at the top of the newsfeed, which posts are displayed in the Explore tab, and which video content (Stories, Reels, Live) to show in their respective sections.

Like with Facebook, Instagram will look at a user’s previous behaviour to then predict how interesting each post is to the user based on their previous engagement with similar content. Once again, like Facebook (it’s almost as if the two companies are connected), Instagram will use a number of ranking signals, with the most important ones being:

  • Relationship: The more two users engage with each other’s content, the more likely it will display in their newsfeed. For a brand this is difficult, however, having a loyal following that engages with your content is recognised by Instagram.
  • Interest: How appealing is each post to the user? Instagram is great at understanding what is in a photo or video understanding if a user is interested in that. Again, for brands, this can be difficult, but focusing on truly engaging content is the best place to start.
  • Timeliness: Quite simple, when was the post uploaded? While the feed isn’t chronological, new posts are more likely to be ranked higher, so understand when your audience are online.

Some of the other ranking factors that Instagram mentions are more focused around your audience’s behaviour as opposed to your own. These include how often they use the platform, and for how long, as well as the number of accounts they follow.

Again, there hasn’t been a huge change in the Instagram algorithm, it has just got better at understanding a user’s interest. Engagement continues to be crucial, as is the case with all social media platforms. In my previous post I mentioned the fact that Instagram could be moving back to a chronological newsfeed, however, these rumours were soon squashed and the current algorithm looks like it’s here to stay.

In general, there haven’t been any catastrophic changes in the algorithms of the above social media platforms. There have just been small tweaks to perfect how each platform decides what content to show.

I have just focused on the three platforms that I highlighted in my previous guide to social media algorithms. However, if you would like more information on tackling the likes of YouTube, LinkedIn, or the new giant TikTok, please feel free to get in touch.

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