An algorithm is a detailed step-by-step instruction or you could say formula for solving a problem or completing a task, most commonly used in computing.

Instagram programmers write algorithms that instruct the app how to perform tasks to get search results and display content on the app, what time and what types etc.

So basically an easy way to understand an algorithm is its just a set of rules and guides written in a programming language that is designed to instruct how an app should function.

How the Instagram algorithm works in 2020

Instagram’s primary goal is to maximise the time users spend on the app. Instagram is a commercial business, owned by Facebook so it's no surprise that the longer users stay on the app, the more ads they see. So directly or indirectly, accounts that help Instagram achieve that goal are rewarded.

Instagram’s top algorithm ranking signals

Relationships

Instagram’s algorithm prioritises content from accounts that users interact with a lot.

If a person often leaves comments on your posts, or if they have notifications enabled for your account, or you DM each other, or you tag each other in your posts, then the algorithm recognises that the two of you are “close.”

Interest

The algorithm also predicts which posts are important to users based on their past behaviour. This potentially includes the use of machine vision (a.k.a. image recognition) technology to assess the content of a photo.

This is similar to how the Facebook algorithm and the YouTube algorithm filter and recommend content. So, users who like foodie photos are more likely to see foodie content at the top of their feed. Users who like architecture animals are more likely to see architecture up there.

Timeliness

The algorithm shows users newer posts first.

For brands, the timeliness (or “recency”) ranking signal means that paying attention to your audience’s behaviour, and posting when they’re online, is critical to content being seen.

Frequency of use

This depends on how often a user opens the app. The algorithm aims to show users the best and most popular posts since they last looked at their feed.

Following count

If a user follows a lot of accounts, they’ll probably see fewer posts from any one specific account, even if that account is prolific. But they’ll see a wider breadth of posts overall. On the other hand, if they follow a smaller number of accounts, they’ll likely see more of each account’s posts.