Instagram users weren't too happy when the platform announced it was implementing a new algorithm in July 2016. It gave higher priority to posts the photo-sharing app believed people cared about most, rather than displaying the most recent posts at the top of its feed.

Instagram says the changes have been effective. Users had been missing half of what their friends posted, the company says. But displaying posts by relevance has led its more than 800 million users to see 90 percent of their friends' posts, and to spend more time on the app, according to TechCrunch and other publications briefed on the matter.

But how does Instagram decide what's "relevant" to you, and how does the ranking algorithm for its feed work? 

According to TechCrunch, the company relies on machine learning based on a your behavior -- who you follow and how you interact with those accounts -- to create a unique feed. 

There are three key factors that come into play here, TechCrunch reports. First, Instagram will predict your interest in a post, and will rank something higher if it thinks something will matter to you more based on your past behavior on similar content. Sometimes, machine vision will analyze the content in the post.

The second factor is how new a post is. Timely posts are prioritized over older ones.

Lastly, if you're closer to a person (based on how much you've interacted with them in the past on Instagram), you'll see more from them. 

There are a few other signals that reportedly impact what shows up near the top of your feed. How often you launch the app is a factor, as Instagram will try to show you what it thinks are the top posts since you last checked in. Also, if you follow a ton of people, the app will pick from a larger pool of people, so you'll probably see less from a particular person. Lastly, how much time you spend on the app determines if you'll be seeing more than just the best posts, but rather the other stuff people are posting, too. 

Instagram told TechCrunch that it doesn't hide posts in the feed. If you scroll for long enough, you should see everything that people you're following are posting. Also, Instagram doesn't favor videos or photos, but if you don't engage with videos very much you'll probably see fewer of them. 

And what about users who post a ton of content? The company reportedly says it doesn't down-rank those users, but if they consecutively post several things it may swap in other content between those posts.  

Instagram had no additional comment beyond the briefing.

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