The Most Complete Google SEO Algorithm Update for 2021

Recently, many colleagues have private chats, and then they also discussed a lot of issues about on-site SEO, and also received encouragement and support from many classmates. This gives me a little more motivation on the way to insist on updating dry goods. Google SEO algorithm is a topic I have been researching.

I think in order to do a good job of website SEO, Google’s historically significant update algorithm needs to be understood clearly. While doing SEO rigorously, you can also better avoid stepping on pits.

This article is based on my research on Google developer’s blog, Google search Twitter, and then combined with my own understanding. The last two paragraphs of the article will set their hyperlinks, and interested friends can click on the corresponding website to read.

Because considering that most of the small partners will need to read this article, in order to avoid too much content, it is too boring to read. So I spent an entire afternoon, from the initial draft of nearly 8,000 words to the current 6,500 words, which can be regarded as a relatively elite article.

A brief introduction to Google’s algorithm

Google’s search algorithm is updated thousands of times every year. Most of these changes are relatively minor updates. However, “core” updates are sometimes announced in advance of their rollout to give webmasters a chance to prepare and optimize accordingly.

If you’re preparing for, and want to benefit from, Google’s algorithm update, the easiest way is to read Google’s SEO documentation for their updates. Essentially, if you can optimize your website from the start so that you produce high-quality content and provide a great experience for users and bots, you don’t need to worry too much.

This article will help you better understand some of the most important “core” algorithm updates Google has made in the past decade to better target your website.

The following is the outline of this article, the content of point 3 and the answer to point 5. It is recommended to watch it repeatedly.

  1. What is Google Algorithm?
  2. How often Google’s algorithm is updated
  3. Major historical algorithm updates
  4. Google’s latest algorithm
  5. How to keep up with Google algorithm updates

What is Google’s algorithm?

Google’s algorithms work in a complex system (say, SEO ranking has over 200 factors) to satisfy search queries in the best possible way. Each Google algorithm uses a set of rules, combined with data from its index, to figure out which web pages best answer a given search query, then the search engine uses its programmed ranking signals to rank search results based on their relevance Organize these pages hierarchically.

How often Google’s algorithm is updated

When Google first started, they didn’t update their algorithms as much as they do today. Now, Google makes thousands of updates, big and small, every year. Most of these are micro-updates that leave webmasters and users relatively unaffected, but every once in a while, Google announces a major algorithm update.

These larger algorithm updates are often events that SEO professionals and webmasters need to plan for. When Google is about to make a major change to its algorithm, it calls it a “core update,” meaning a core part of the algorithm will change that will have a more significant impact on SEO or user experience.

A brief history of Google algorithm updates

Here’s the crux of this article, where I’ve listed the names of Google’s major algorithm updates over the past decade, along with a brief summary of what they’ve been updated and their impact on SEO. There are also updated content and important keywords that affect SEO. I will mark them in bold below, so that everyone can read and remember. Learning the Google SEO algorithm will help you do anything on your website.

The Caffeine Index Algorithm (2010)

Panda Algorithm (2011)

Penguin Algorithm (2012)

Venice Algorithm (2012)

Pirate Algorithm (2012)

Hummingbird Algorithm (2013)

Pigeon Algorithm (2013)

HTTPS/SSL (2014)

Mobile Friendly Algorithms (2015)

RankBrain Algorithm (2015)

The Possum Algorithm (2016)

Intrusive Interstitial Ads Algorithm (2017)

Movement Speed ​​Algorithm (2018)

Doctor Algorithm (2018)

Burt’s Algorithm (2019)

Featured Snippet Algorithm (January 2020)

Paragraph Ranking Algorithm (February 2021)

Product Review Algorithms (April 2021)

Page Experience (June 2021)

Caffeine Indexalgorithm(2010)

In June 2010, the caffeine index (CAFFEINE INDEX UPDATE) was updated. The new indexing system is designed to speed up search results for users and help publishers see their content faster.

It helps Google crawl and store data more efficiently. According to Google, “Caffeine web searches provide fresher results than our last index, and it’s the largest collection of web content we offer.

This algorithm change is an overall effort to speed up the internet and meet the demands of a rapidly growing network. Therefore, in order to complement this overall task,Googleat the same timeAnnouncing site speedwill be a ranking signal for Google.

Impact on SEO.

Although the Caffeine Index update doesn’t include any new ranking factors, the update is part of Google’s overall “Accelerate the Internet” initiative, which makes desktop site speed a new ranking signal and emphasizes the importance of site performance.

Caffeine gives users a better experience by enabling Google to index more content across the web.

pandas algorithm(year 2011)

The Panda update introduces a new ranking signal, as part of Google’s mission to provide users with quality content, itPenalized content farms and keyword stuffing. It improves search results by identifying thin, spam, and low-quality content and then removing it from top search rankings.

Impact on SEO.

Many members of the SEO community had to change their strategies.blowBlack hat SEO tacticssuch as keyword stuffing, is no longer as effective, and SEOs have to make adjustments to ensure that content truly provides value to readers and effectively answers search queries.


The PENGUIN UPDATE update is designed to target sites that have spam and use manipulative link building tactics. Google calls it a “spam algorithm update.”

Thanks to this update, the algorithm is now able to identify whether a link back to a page is legitimate or just spam.

Impact on SEO.

The Penguin update also targetsBlack hat SEO techniques.Manipulative LinksBuilding techniques no longer work, and backlink profiles with lots of low-quality links start to see their organic traffic and rankings drop.

Following the Penguin update, non-compliance with Google’s webmaster guidelines resulted in a ranking penalty.

Venicealgorithm (2012)

This algorithm has little relevance to our SEO

An update to the Venice algorithm (VENICE) improves search results for products and services, bringing them closer geographically to searchers. Searchers can expect to more reliably find results from within or very close to their city or town. Think of queries like “fitness centers near me” or “fitness centers in Boston”. After this update, 10 blue links in search results are more likely to offer local options.

Impact on SEO.

This update has had a huge impact on local SEO, especially for small businesses and brands. Now, they can compete with larger businesses and brands for high-traffic keywords with local intent.


This algorithm has little relevance to our SEO

The Pirate Algorithm (PIRATE) update is to prevent sites with reports of copyright infringement from ranking high in Google’s search results. Google recognizes that piracy is a big problem, so they fight it by verifying any reports of copyright infringement that violate the Digital Millennium Copyright Act (DMCA).

Impact on SEO.

If your site violates the DMCA and Google is able to verify it, its ranking in organic search results will be severely degraded.

Hummingbird Algorithm (2013)

The update of the HUMMINGBIRD algorithm has greatly affected the search engine experience.This update allows Google to better understand what we’re talking about “Search Intent”. It enables search engines to more accurately combine user queries and website information and connect the two.

Impact on SEO.

Hummingbird update finally makes it easier for users to findmost relevant pagesto answer their inquiries.This encourages the search community to investigate betterSearch intent behind specific keywordsand try to optimize it.

pigeon algorithm (2013)

The pigeon algorithm (PIGEON) focuses on improving local search. Pigeon aims to bridge the gap between Google’s local search algorithm and Google’s web algorithm to improve ranking parameters based on physical distance.

Impact on SEO.

The pigeon update had a huge impact on the local search community. It makes it easier for small businesses to reach local audiences. Now, if small businesses implement basic SEO best practices — like gaining backlinks and growing domain authority — it can improve their ranking chances.

Also, thanks to Pigeon, it is now more important for small businesses to include their business as local in their content, follow local SEO practices such as getting local reviews, and implement structured data markup to facilitate localization appears in the rich results of the search.

https/ssl (2014)

The HTTPS/SSL update is part of Google’s “HTTPS Everywhere” campaign to make the internet more secure and ensure users access trustworthy and secure websites from search results. In short, they encourage webmasters to move their website from HTTP to HTTPS protocol by installing an SSL certificate on the website server.

Impact on SEO.

In this update, Google is making HTTPS a lightweight ranking signal and setting new user expectations for the level of trust and security in its organic search results.

mobile friendlyalgorithm(2015)

Mobile friendly (Mobilegeddon) Updated April 2015. This will be the solution to Google’s “The first major update to the Mobile First” initiative.In order for a page to be considered mobile friendly, it needs to meet certain visual requirements. Specifically, its proportions need to be in favor of the screens of mobile devices (smartphones).

Impact on SEO.

Mobile friendliness becomes a new ranking signal.Pages that offer mobile-friendly versions are now prioritized in search results.


RankBrain update introduces newmachine learning artificial intelligenceto help determine the most relevant search results for a query. The update of this algorithm is a relatively significant breakthrough, and Google has indicated that it will continue on the basis of this algorithm for a long time. With this update, queries go through an explain model that can apply any combination of factors, such as location and word count, to determine intent and deliver the most relevant possible results.

Impact on SEO.

With this update, different ranking signals now apply to different queries. It all boils down to whatever query best meets the user’s needs. Optimizing for standard factors is not necessarily sufficient.


The possum algorithm (Possum) improves local search results. Before this update, businesses located outside the actual city limits of a place had a very hard time ranking for relevant keywords. This update resolves such an issue. It also makes the actual location of the searcher more important, while also making it more sensitive to changes in local terms.

Impact on SEO.

This is an important local SEO update. Google has improved its address and location-based filters, taking steps to diversify results and further prevent spam from ranking well.

Intrusive mid-roll ads update (2017)

In 2017, Google updated its algorithm (INTRUSIVE INTERSTITIALS UPDATE) to reduce so-called intrusive mid-roll ads. Intrusive intermediary ads are essentially large pop-up ads. They are ads that cover a large portion of a page, making it harder for users to view the content of the page and find the information they need.

Google explained that the intent of this update is to keep spam to a minimum and enhance SEO, but even if the content has intrusive intermediary ads, it can still get high if it effectively answers a user’s search query. search ranking.

Impact on SEO.

Thanks to this update, intrusive middle ads became an SEO ranking penalty.

Mobile Page Speed ​​Update (2018)

In January 2018, Google released a “velocity update” to the algorithm that will include new ranking signals that are beneficial in mobile search resultsfast mobile pagepage. The update is part of Google’s overall “Accelerate the Internet” initiative and Google’s “Mobile First” initiative.

To measure fast mobile speeds and more accurately reflect the mobile loading experience of real users, Google announcedPageSpeed ​​InsightsData from the Chrome User Experience Report will now be included, and they explain what load metrics developers and webmasters need to be aware of. At the time, Google tended to put First Contentful Paint ( FCP ) and DOM Content Loaded ( DCL ) as the two most important metrics for a fast loading experience that can – this has since changed.

Impact on SEO.

Mobile page speed updates make mobile page speed a ranking factor in mobile search results. Sites with really fast moving pages perform better in search results, while slow pages lose rankings. SEO needs to work with developers or software to solve the mobile speed problem.

Doctor Algorithm (2018)

Updates to the Physician Algorithm (Medic) improve access to online contentExpertise, Authority and Trust (EAT)identification.

Impact on SEO.

There are many factors that affect EAT. At the time of this update, if your site has minimal comments and backlinks, thin content, infrequent updates, or lacks a comprehensive profile of the business and content author, your page may be pushed down in search results in favor of completion Links to more of this checklist.

If you want to know more about EAT, please jump to

On-site SEO Part 6: Important Factors Affecting SEO EAT


BERT’s algorithm (Bidirectional Encoder Representations from Transformers for short BERT) is a natural language processing machine learning system. It helps search engines understand what words in sentences mean to humans. Updates to BERT allow Google to understand search queries more efficiently and determine which content is of higher quality and more relevant to user search queries. After BERT, Google can determine word nuances and subtle differences of meaning based on context.

Impact on SEO.

BERT has changed the way SEO copywriters write topics. Specific keywords become less important, and natural language associated with specific keywords becomes more important. If you write high-quality content on a given topic, give the right information, and talk to others who have already written on that topic (citing sources), then Google’s algorithm should be able to spot that.

Featured Snippetrenew(January 2020)

Featured Snippets Update (FEATURED SNIPPETS) Removed URLs from search results pages containing Featured Snippets. For example, if your page gets a featured snippet for a particular query and also comes second with one of the standard blue links, your URL will be removed from that list because Google decides to feature Snippets count as one of the 10 links displayed.

Impact on SEO.

For example, fewer hits go to the featured snippet than to the first standard organic listing. Therefore, there is reason to worry that sites ranking in these two or similar positions will experience a significant drop in traffic from these queries.

paragraphrankingalgorithm(February 2021)

PASSAGE RANKING makes it possible for Google to rank specific paragraphs in web pages in search results. The motivation for this update is that it was previously difficult to satisfy very specific search intents, as answers were often buried deep within web page content. Consider the analogy of finding a needle in a haystack here. The solution is for Google to consider the content and meaning of specific passages on a web page when considering the most relevant search result rankings.

Impact on SEO.

Because Google can now pull your content out and rank it separately from the rest of the page, some forms of on-page SEO become more valuable. For example, the title tag at the bottom of the page has become more important. The same is true for long-tail keywords. Also, there is more incentive to write long-form content because Google is now able to parse it better.

Product Reviewsalgorithm(April 2021)

Product Review Updates (PRODUCT REVIEWS) better reward reviews from expert and hobbyist publishers for in-depth research and analysis. Previously, thin, templated, and snippet-based reviews were easy to rank well in Google searches.

Impact on SEO.

Google doesn’t penalize sites themselves that have suboptimal reviews. Instead, they just ranked more comprehensive review content above these results. In Google’s own documentation about the update, they provide a list of issues to use when building reviews. For example, ask yourself whether your reviews express expert knowledge, demonstrate how the products are used, how they differ from alternatives, and whether they address key decision-making or purchasing factors.

Page Experience (June 2021)

The Page Experience update adds three new core web metrics (Maximum Content Painting, First Input Latency, and Cumulative Layout Shift) to the Page Experience ranking factors, which previously included Mobile Friendliness, Safety, Safe Browsing, and Distractions Sexual intermediary ads. These three new page experience signals measure website loading speed, responsiveness, and visual stability to fully measure user experience.

Impact on SEO.

The update penalizes sites that are slow to load important content above the fold, slow to respond to user clicks on buttons and links, and sites that are visually choppy — for example, ads that load on the screen by moving parts of the content you’re reading out of the way location.

Google’s latest algorithm

In June 2021, Google will release another core algorithm update. The purpose of this update is to improve the loading experience for users, or what Google calls the “page experience.” The update will include new ranking signals, called “Core Page Elements,” consisting of three load metrics: Maximum Content Size (LCP), First Input Latency (FID), and Cumulative Layout Shift (CLS).

The update is also part of Google’s overall “speed up the Internet” initiative and will benefit sites that score “good” on all three metrics, although it’s just one of many ranking factors that we should take seriously.

How to increase page speed.

There are many things you can do to improve your core network vitals, and each metric requires a different solution and some troubleshooting.

How to keep up with algorithm updates

If you want to keep up with algorithm updates, your best bet is to follow Google’s major search news, such asChromium Blog,Google Developer Blogand their search-focused Twitter accounts@googlesearchc. Another great resource for learning about algorithm updates isSearch Engine Magazine.


How does Google’s algorithm work?

Basically, Google’s ranking system is made up of a series of algorithms. These search algorithms look at many factors around the following 5 dimensions:The meaning of the query, the relevance of the page, the quality of the content, the usability of the page, and the context and settings that provide the best results. The weight applied to each of these categories depends on the nature of the query.

What is Google’s latest algorithm update?

The latest core algorithm will be launched in June 2021. It’s called the “Page Experience” update, and it will penalize sites with poor user experience for everything from loading speed, responsiveness, and visual stability, and whether the site is safe and safe to browse, mobile-friendly, and has good ad experience to measure.

How often will Google change their algorithm?

Google updates its algorithms thousands of times a year. Most changes are small and go unnoticed by webmasters. Occasionally, Google announces major “core” algorithm updates and will give webmasters plenty of lead time to prepare accordingly for the changes that will be rolled out.

Why did Google change their algorithm?

Google’s mission is to organize the world’s information in an accessible and useful way. Their algorithms are getting better at delivering a good user experience in search results, but it’s a work in progress. Each algorithm update is a step forward in their mission to provide the best possible search results.

What’s the best way to prepare for Google’s algorithm update?

In fact, the best way to prepare for Google’s algorithm changes is simply to focus on producing great content on a technically sound site with high-quality external and internal links. If you’re doing it with the normal algorithm, you don’t need to worry too much.If you are still very worried, it is recommended that you pay attention to Google’s main search news, such asChromium Blog,Google Developer Blogand their search-focused Twitter accounts@googlesearchc.

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