Google algorithm updates were the big SEO trend of 2021 with one of the busiest update roadmaps we’ve seen in recent years. Aside from the pre-announced page experience update and the usual core updates expected every year, Google hit us with a string of surprises and the summer period, in particular, was one of the most volatile we’ve seen.
In this article, we take a look at all of the algorithm updates that mattered in 2021, summarise the key takeaways from each of them and analyse what they mean for search marketing in 2022.
As we explain in our recent biggest SEO challenges article, Google hit us with a lot of algorithm updates this year and the summer period was particularly intense. At one point we had three updates in the space of one month and half a dozen over a three-month period, rolling out almost back-to-back.
As always, some updates make more of an impact than others and there are always winners and losers from one update to the next.
However, when you look at the collective impact of this year’s heavy update schedule, it’s had a significant impact on ranking volatility. Back in October, Head of Communications at Semrush, Mordy Oberstein, published data from the Semrush Sensor tool showing how volatility in the SERPs has increased this year.
If you're following @rustybrick's algo update coverage he's pretty tired of reporting on these all the time!It got me thinking: Are things more volatile than they were? Pulled some @semrush data & it seems… YES!We see a huge increase in the % of volatile days in '21! pic.twitter.com/vmTP5vtaJh— Mordy Oberstein (@MordyOberstein) October 19, 2021
If you're following @rustybrick's algo update coverage he's pretty tired of reporting on these all the time!It got me thinking: Are things more volatile than they were? Pulled some @semrush data & it seems… YES!We see a huge increase in the % of volatile days in '21! pic.twitter.com/vmTP5vtaJh
The frequency of updates this year has also made it difficult to analyse each one in isolation. Normally, we have weeks or months to attribute ranking changes to major algorithm updates and identify which signals are affected by each one.
This year, the busy update schedule and the back-to-back rollout during the summer, in particular, made it harder to attribute changes to specific updates.
With that in mind, let’s take a look at all of the algorithm updates from 2021 and explain what we know (and don’t know) about them.
This year, we’ve had 10 algorithm updates announced and/or confirmed by Google. Every year, there are an unknown number of unconfirmed updates, most of which have a moderate impact on rankings or such a small impact they’re barely distinguishable from regular movement in the SERPs.
However, this year, three unconfirmed updates each had a major impact on results so we’re including all 10 confirmed updates and the three unconfirmed that shook things up this year:
Now, let’s take a look at each of these updates and what has changed for search marketers this year.
The first algorithm update of 2021 landed on 10 February, commonly referred to as passage indexing although passage ranking is probably a more suitable description. The update didn’t have a major impact on ranking positions and it was more of a new feature introduction than the kind of algorithm update we’re used to seeing from Google.
That said, the new feature does change how Google’s algorithm indexes and ranks content.
Passage ranking is an AI-powered update designed to help Google return the best result for “very specific” searches. Essentially, the update allows Google to rank a passage that specifically addresses the user’s search query, even if the page itself is optimised for a different keyword.
For example, let’s say you have an in-depth blog post covering a broad topic, such as buying a second-hand car. Your primary keywords will be things like “buying a second-hand car,” “how to buy a second-hand car” and “what to check when buying a second-hand car”.
Your page title, headings and content will be optimised for keywords like this but your guide may include a section on the common financing options available to people buying used vehicles from a dealer.
Now, someone searching for information on the differences between Hire Purchase (HP) and Personal Contract Purchase (PCP) financing options may see your buying guide because Google understands the intent of their specific query and your comparison provides the best answer to their question, even if other posts are better optimised for the query.
Here’s what Google has to say about the update:
“Very specific searches can be the hardest to get right, since sometimes the single sentence that answers your question might be buried deep in a web page. We’ve recently made a breakthrough in ranking and are now able to better understand the relevancy of specific passages. By understanding passages in addition to the relevancy of the overall page, we can find that needle-in-a-haystack information you’re looking for.”
Google says passage indexing (or ranking) will affect seven percent of search queries across all languages as it rolls out gradually. This began in the US for English results on 10 February and continues to roll out globally.
On 19 February, MozCast reported a 40% decline in visibility for Featured Snippets, which plummeted to their lowest point since 2015. In many cases, Featured Snippets disappeared altogether and the impact was especially hard on health and finance queries.
Moz’s Dr. Peter J. Meyers published a blog post covering Featured Snippet visibility from February 10-23 with no signs of recovery.
Delving into the data, Meyers saw that health queries experienced the biggest decline with a -68% drop in Featured Snippets while finance came in at a close second with a -60% decline.
It turned out the biggest drops were seen for short queries, particularly single-word queries, and pages considered as YMYL were hit hardest (this explains the heavy hit on health and finance).
The key takeaway? Make sure you’re up-to-date with the latest on E-A-T and YMYL and update your content to meet Google’s expectations, especially if your pages qualify as YMYL.
Precisely three weeks after 40% of featured snippets mysteriously disappeared from Google Search, they miraculously reappeared on 12 March with the same ranking positions as before.
To this day, Google has given no explanation for the disappearance or reappearance of Featured Snippets nor confirmed whether the episode was the result of an algorithm update gone wrong, a bug or anything else.
The closest thing we got to an explanation was general commentary from Google’s John Mueller who was careful enough not to reference the sudden drop and reappearance in February and March:
“I don’t know. …The featured snippets and rich results in general, those kinds of things can fluctuate over time.
And I know the teams are always working on those features and trying to fine-tune the triggering.
So when we would show them or when we wouldn’t show them, sometimes the triggering changes over time that we just kind of reduce the threshold overall or that we change the focus a little bit and say like less here and more here. Sometimes that happens across geographies or languages.
But these kinds of changes from our side are essentially normal organic changes in search, how they can always happen.”
That’s a typically diplomatic response from John Mueller but the Featured Snippet disappearing trick was anything but “normal organic changes”.
On 8 April, Google announced an update specifically targeting product review content. After a testing, experimentation and review process, Google determined that a lot of review content doesn’t deliver information that truly helps people make purchase decisions.
Here’s what Google said in its announcement.
“From this, we know people appreciate product reviews that share in-depth research, rather than thin content that simply summarizes a bunch of products. That’s why we’re sharing an improvement to our ranking systems, which we call the product reviews update, that’s designed to better reward such content.
This update is going out today and only involves English language reviews for now. We believe this will further help those producing rich content in the product reviews area.”
To bring review content up to its new expectations, Google provided a list of questions you should ask before publishing and updating any reviews on your website.
Do your reviews:
Google clarified that the product reviews update was not a core algorithm update but it did state that Google’s usual advice for core updates did apply. We can’t confirm what Google meant by that but we expect it relates to content quality and the increased importance of E-A-T and YMYL.
For example, product reviews should be written by someone with proven experience and expertise on the product categories in question with their author bio and relevant links included in every post. For example, laptop reviews should be written by experienced tech reviewers who know their stuff, can go into detail and genuinely help people choose one device over the other options available to them.
Mordy Oberstein published a great writeup of the update’s winners and losers on Search Engine Journal, showcasing how the update was more complex than simply targeting thin content or affiliate links.
The big winners were pages that include buyer’s guides, comparison tables and calculations to help shoppers choose the ideal product for their needs. Affiliate content disguised as product reviews has suffered the most and Google is a lot more capable of detecting this type of content now.
On 2 June, Google took the surprising step of announcing not one, but two core algorithm updates – one rolling out later in the day and another in the following month. The reason for the double update was simple enough: “Some of our planned improvements for the June 2021 update aren’t quite ready, so we’re moving ahead with the parts that are, then we will follow with the rest with the July 2021 update”.
Later today, we are releasing a broad core update, as we do several times per year. It is called the June 2021 Core Update. Our guidance about such updates is here:https://t.co/e5ZQUA3RC6This will be followed by the July 2021 Core update. Here’s more information about that…— Google SearchLiaison (@searchliaison) June 2, 2021
Later today, we are releasing a broad core update, as we do several times per year. It is called the June 2021 Core Update. Our guidance about such updates is here:https://t.co/e5ZQUA3RC6This will be followed by the July 2021 Core update. Here’s more information about that…
Once again, websites with thin content lost out from the first update and YMYL pages suffered more than most – not for the first time in recent years. That being said, some of the winners from the June 2021 Core Update were losers from previous core updates and this was another reminder that updates themselves are experimental and Google is willing to correct itself when it takes things too far.
The June 2021 Core Update also kicked off the busy summer of updates – some of which we knew about, many we didn’t.
The next summer surprise from Google was a spam update announced on 23 June via Twitter. Once again, Google told us that another spam update would follow, this time during the next week.
As part of our regular work to improve results, we've released a spam update to our systems. You can learn more about our efforts to fight spam in this post:https://t.co/piCLhbZPkHAnd this video below:https://t.co/xMYWm4HPze pic.twitter.com/83IL0EB9Lm— Google SearchLiaison (@searchliaison) June 23, 2021
As part of our regular work to improve results, we've released a spam update to our systems. You can learn more about our efforts to fight spam in this post:https://t.co/piCLhbZPkHAnd this video below:https://t.co/xMYWm4HPze pic.twitter.com/83IL0EB9Lm
Google pointed towards an updated list of webmaster guidelines ahead of the first update, including general guidelines and quality guidelines for website owners.
Above all, you should avoid all of the following:
You should also monitor your website for hacking and take steps to prevent and remove user-generated spam on your site. This will become increasingly important as attacks against websites and spam techniques continue to become more sophisticated.
Google announced the page experience signal in June 2020, giving us plenty of time to prepare for the update on 25 June, 2021. The update combined several existing signals related to user experience with the newer Core Web Vitals signals that measure loading times, the responsiveness of interactive elements and the visual stability of pages.
The cumulative page experience signal combines these independent signals into a single measurement for Google’s algorithm, allowing it to grade the overall quality of user experiences on individual pages.
Currently, there are three Core Web Vitals included in the page experience signal although Google says it may expand upon these over time:
Google initially suggested the impact of the page experience update could be mild, stating that quality is the determining factor in rankings. It said the page experience signal could help differentiate between two pages of similar quality.
It turns out, Google may have done a better job of playing down the update than it intended and Danny Sullivan later insisted that it could have a bigger impact over time, even if the overnight effects were small.
I said it shouldn't be the case that overnight, we flip some type of switch and there's a massive change. That's not typically how rollouts of this nature (such as speed, mobile-friendly) have worked. And also that things tend to be relative…— Danny Sullivan (@dannysullivan) February 24, 2021
I said it shouldn't be the case that overnight, we flip some type of switch and there's a massive change. That's not typically how rollouts of this nature (such as speed, mobile-friendly) have worked. And also that things tend to be relative…
Of course, ranking signals aren’t the only reason you need to provide a positive user experience and the Core Web Vitals aspect of the page experience update shows Google is taking UX more seriously.
Take a look at our guide on optimising for Core Web Vitals and the page experience signal for more information.
Currently, the page experience signal only applies to mobile pages but Google’s Jeffrey Jose says it will be applied to the desktop ranking system in February 2022.
Google rolled out its Multitask Unified Model (MUM) on an unspecified date in June 2021 and the busy summer of updates makes it difficult to pinpoint a date. Technically, the passage indexing update rolled out in February is a part of MUM so this could be counted as an extension or the completion of a much larger update or the start of an update that could take months or years to make its full impact.
MUM replaces BERT and Google says the new technology is 1,000x more powerful than its predecessor, allowing the search engine to understand complex queries to a greater degree. MUM also allows Google to multitask more effectively, pulling in content from multiple languages and translating it into the source language of the original query.
Much like BERT, it could take several years for the new technology to mature and have a major impact on the SERPs but Google is already teasing a new search experience, powered by the AI technology for 2022.
Google didn’t hang around with the July 2021 Core Update, rolling it out on the first day of the month. The follow-up to the June 2021 Core Update had a smaller overall impact but it hit harder and faster than the gradual rollout of the first update, peaking on 1 July and showing intense fluctuations in the following days.
The Semrush Sensor tool showed volatility was 42% more dramatic than the first core update of the summer.
As with all core updates, it’s difficult to pinpoint the signals being affected and Google pushes the message that you can’t optimise for core algorithm updates. If you experience a decline in traffic from one core update, you’ll also often experience some kind of recovery during the next one or, in the worst cases a double hit if you’ve got serious issues with your pages.
You can read Google’s take on this Search Central blog post.
On July 26, Google announced a link spam update that would roll out over the coming two weeks but, ultimately, took a full month to finish rolling out. Search Quality Analyst at Google, Duy Nguyen, said that although “link spam has been greatly reduced over the past two decades, thanks to our constant improvements in our ranking systems and spam detection systems.”
“This algorithm update… is even more effective at identifying and nullifying link spam more broadly, across multiple languages. Sites taking part in link spam will see changes in Search as those links are re-assessed by our algorithms.” – Duy Nguyen, Search Quality Analyst at Google
The update didn’t penalise sites for spammy links but nullified any ranking benefits so sites with major issues in their link profiles could experience ranking hits that felt a lot like a penalty.
If your site experienced a heavy hit during this period, the only course of action you could take is to analyse your link profile and identify drops in traffic with suspect inbound or outbound links.
To prevent any nasty surprises with updates like this (or link penalties), run regular link audits to identify low-quality or potentially harmful links in your profile. Remove anything that looks suspicious and follow Google’s guidelines to protect yourself from future link spam updates.
In mid-August, SEOs started reporting a significant increase in Google rewriting page titles in the SERPs. While Google often adapts page titles to make them more relevant to user queries, the frequency and extent of changes being reported in the second half of August were extreme – and, at times, erroneous.
On 24 August, Google confirmed an algorithm update that adapted the search engines process for generating web page titles in SERP results.
“Last week, we introduced a new system of generating titles for web pages. Before this, titles might change based on the query issued. This generally will no longer happen with our new system. This is because we think our new system is producing titles that work better for documents overall, to describe what they are about, regardless of the particular query.” – Danny Sullivan, Search Liaison at Google
Regardless, the chatter from SEOs on social media suggested most were unhappy about losing further control over how their page titles show in search. On 27 September, Google updated its announcement of the update, thanking SEOs for the feedback and confirming that further changes had been made to the new system.
As a result, the frequency and degree of changes to page titles calmed from their peak in mind-August but Google still has more power over your page titles than before the update. Google insists that a “focus on good HTML title tags” is still important and published new guidelines for website owners on the Search Central website.
Over the weekend of 2-3 October, SEOs and reporting tools signalled major volatility in the SERPs with the kind of fluctuations you would normally expect from a core update. With no announcement from Google and no confirmation after widespread reports of volatility, this one has to go down as an unconfirmed update.
These happen all the time but they’re not always significant and rarely comparable to core algorithm updates.
One explanation is that the volatility could have been a correction from one of this year’s core updates or some of the feature testing Google has performed throughout the year. Aside from that, we can only speculate, especially with the frequency of updates during the summer months making it more difficult to analyse movement in the SERPs.
On November 3, Google announced another spam update, the fourth one rolled out this year.
As part of our regular work to improve results, we've released a spam update to our systems. This November 2021 spam update should be fully rolled out within a week. We encourage sites to follow our best practices for Search: https://t.co/jK3ArQmTqT— Google SearchLiaison (@searchliaison) November 3, 2021
As part of our regular work to improve results, we've released a spam update to our systems. This November 2021 spam update should be fully rolled out within a week. We encourage sites to follow our best practices for Search: https://t.co/jK3ArQmTqT
While this update was significant, it only affected websites clearly involved in spam or compromised by hacks. As long as you’re following Google’s webmaster guidelines and running the essential security measures, you shouldn’t run into any problems with updates like these.
That being said, it’s worth noting that Google has taken a big stand against spam with four updates this year.
This big question heading into 2022 is whether the busy schedule of updates this year was a one-off or the new normal for SEOs. We know that Google delayed at least one algorithm update in 2020 due to the pandemic so perhaps this year’s hectic schedule was simply the result of several updates being squeezed into 2021.
That said, we also know Google has teased significant changes to the search experience for 2022 and these changes are powered by its new Multitask Unified Model (MUM) technology, which is expected to expand in a similar fashion to BERT before it.
The good news is, we don’t have any major pre-announced updates for next year, as we’ve had in the past with the page experience, mobile-friendly and other updates. However, there is another “but” in the sense that the page experience signal will be applied to desktop ranking in February 2022.
As we discussed earlier, Danny Sullivan has also hinted that the page experience update could have an increased impact over time so we may start to see more influence in 2022.
The big issue for search marketers is that it’s been even more difficult to analyse updates in 2021 due to the busy schedule and overlap of updates this year, especially during the summer months where updates were sandwiched by others.
Here’s a summary of what we do know from the updates in 2021:
If you’re worried you may have been hit by one of Google’s algorithm updates, we can help. Call us on 023 9283 0281 or click below and we’ll be in touch.
Kerry has been working in digital marketing almost since the beginning of the World Wide Web, designing her first website in 1995 and moving fully into the industry in 1996 to work for one of the very first web design companies. After a successful four years, Kerry moved to an in-house position for a sailing company, running the digital presence of their yacht races including SEO, PPC and email marketing as the primary channels. A stint then followed at another in-house role as online marketing manager.
Kerry moved to Vertical Leap in 2007, making her one of the company’s longest-serving employees. As a T-shaped marketer – able to advise on digital strategy outside her main specialism – she rose through the ranks and in 2012 became the head of the Small and Medium Business (SMB) SEO team. In 2022 she became Vertical Leap's Automation and Process Manager.
Kerry lives in the historic town of Bishops Waltham with her husband and daughter. When she’s not at work she enjoys cooking proper food, curling up with a good book and being a leader for Brownie and Rainbow Guides.
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