How the YouTube Algorithm Works in 2021

Since its launch in 2005, YouTube has become more than just a platform for users to upload, share, and watch videos. It’s now the second-largest search engine in the world—and a valuable tool for brands and creators alike.

  • YouTube attracts more than 2 billion monthly logged-in users
  • Over 1 billion hours of video are watched each day on YouTube
  • 500+ hours of content is uploaded to YouTube every minute
  • 84% of people have been convinced to buy a product or service by a brand’s video
  • A recent survey found that 93% of marketers currently using video consider it “an important part of their marketing strategy”
  • More than one-third of consumers have purchased products they discovered on YouTube

How does YouTube decide which videos to recommend to users?
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A Brief History of YouTube Algorithm Changes

While YouTube hasn’t released the technical details of the algorithm, here’s a brief overview of how it works:
1. Remove: YouTube prioritizes removing content that violates their policy as swiftly as possible.

2005 to 2012: View Count

Additional ranking signals include:

2012 to 2015: Watch Time

To make the most of YouTube’s SEO algorithm, creators and brands need to optimize metadata. Metadata includes your video’s title, description, and tags.

2016: YouTube introduces “deep learning” for recommendations

2. Engagement metrics (Watch time, likes, comments, etc.)
Recommendation factors include:

YouTube recommendation system architecture
1. Keyword relevance based on metadata (Title, description, and keywords)

1. Keyword relevance based on metadata (Title, description, and keywords)

1. Keyword relevance based on metadata (Title, description, and keywords)

1. Keyword relevance based on metadata (Title, description, and keywords)

Before we dive into YouTube’s current algorithms, here is a quick timeline of how YouTube has ranked videos from the platform’s inception through today.

Video content that isn't eligible for advertising on YouTube
SEO tools like Ahrefs and Ubersuggest can help creators identify popular searches and related keywords. Keyword-rich titles and descriptions make it more likely that videos will show up in relevant searches.

By optimizing your videos using the tips we shared today, and keeping an eye on these reports and metrics, you will be well on your way to making the YouTube algorithms work for you.

All in all, videos that answer users’ questions and hold viewers’ interest will benefit the most from YouTube’s ranking algorithm.

In 2019, YouTube began systematically removing “borderline” content, meaning content that comes close to violating the Community Guidelines and spreads harmful misinformation. YouTube also announced over 30 changes designed to “raise authoritative voices on YouTube and reduce the spread of borderline content and harmful misinformation.”

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Unlike suggested videos, trending videos are not tailored to each user. Instead, to determine which videos are trending, YouTube considers popularity (view count) and novelty (view velocity).

YouTube Studio Analytics

YouTube’s primary source of revenue is advertising, and they understand that there is an abundance of content on their platform that most brands won’t want their ads to show alongside. With this in mind, they have created advertiser-friendly content guidelines for Creators who want their videos to be ad-eligible. Their channel is also required to follow YouTube monetization policies, which include YouTube Community Guidelines, and Google AdSense program policies.
YouTube has multiple algorithms for ranking content on the home page, search results, and suggested videos. In this article, we’ll explain how YouTube’s algorithms work, and how you can make the most of them.
The description field helps viewers find your video and decide if they want to watch it. The first few lines of your description will show up on the SERP and on the video page before the “Show more” link. You can add additional information (and keywords) below the “Show more” break.

  • Traffic source types: How viewers found your videos
  • Suggested videos: Traffic from the “Suggested Videos” lists that appear next to or after other videos and from links in video descriptions
  • Impressions and how they led to watch time: How many times your video’s thumbnails were shown to viewers, how frequently those thumbnails resulted in a view, and how those views led to watch time
  • Playlists: Traffic from the most-watched playlists that include your videos
  • YouTube search: Traffic from search terms that brought viewers to your content

To see which videos bring viewers to your channel from “Suggested Videos,” take a look at the “Traffic Sources” report in your YouTube Analytics dashboard.