Google’s SEO Algorithm History

The November 16th 2021 Confrimed

Core Update is now rolling out live. As is typical with these updates, it will typically take about one to two weeks to fully roll out.

Page Experience Update — June 25, 2021
Confirmed

After multiple delays, Google started rolling out the Page Experience Update on June 25th, announcing that the rollout would continue through August 2021. This update included Core Web Vitals and impacted both organic results and News results (including Top Stories).

Spam Updates — June 23, 2021
Confirmed

Google released two spam updates, on June 23rd and June 28th. It was unclear how the two updates were connected or what specifically was impacted. While specific sites showed significant impacts, there was no clear impact on overall rankings volatility.

June 2021 Core Update — June 2, 2021
Confirmed

In an unprecedented move, Google simultaneously announced the (apparently connected) June and July 2021 Core Updates. The June Core Update reportedly rolled out from June 2-12, peaking in MozCast at a temperature of 107.3°F on June 3rd.

Rank tracking tools and webmaster chatter suggested a significant update, with MozCast measuring 101°F, but no update was confirmed by Google. Some industry analysts suggested the changes were rolled back the next day and may have been temporary.

Google Glitch — August 10, 2020

Confirmed

SEOs reported massive ranking changes for a few hours on August 10, which then seemed to disappear. Google later confirmed a glitch in their indexing systems. MozCast registered 97°F the following day (August 11), but it's unclear if this event was related.

Google Bug Fix — June 22, 2020

Unconfirmed

Rank-tracking tools showed heavy flux, with MozCast reaching 96°F. While no algorithm update was confirmed, a Google rep confirmed an indexing bug affecting Disqus comments that would be fixed during this time period.

May 2020 Core Update — May 4, 2020

Confirmed

Google announced another Core Update (the second of 2020), which caused heavy rankings flux from about May 4-6. Peaking at 113°, it measured on MozCast as the second-highest Core Update after the August 2018 "Medic" update.

COVID-19 Pandemic — March 11, 2020

Unconfirmed

While not an algorithm update, per se, COVID-19 dramatically shifted consumer search behavior. The WHO pandemic declaration on March 11th seemed to be a pivotal turning point. In March on MozCast, 16 out of 31 days topped 90°F, and rankings were in high flux well into April and May.

Google’s SEO algorithm history in complete order from 2015 to present time in July 2017. As you know Google uses multiple algorithms in each search query. I’ve gone out of the way to publish a list so my clients will have an understanding. A complete list of 2018 and 2019.

2019 Updates

Site Diversity Update — June 6, 2019

Confirmed

Google pre-announced a “site diversity” update, claiming it would improve situations where sites had more than two organic listings. Moz data showed that, while the update did marginally improve SERPs with 3-5 duplicate sites on page one, the impact was relatively small.

June 2019 Core Update — June 3, 2019

Confirmed

Google pre-announced a “core” update, but with limited details. Sites impacted in previous core updates seem to have been affected, in some cases, and some major UK publishers reported heavy losses. On average, the impact was smaller than the August “Medic” update, as measured by MozCast.

Indexing Bugs — May 23, 2019

Confirmed

Two days in a row, Google confirmed indexing bugs. The first bug reportedly was preventing new content from being properly indexed. MozCast confirmed unusually high SERP flux from May 23-25 (peaking on the 23rd), but it’s unclear if this was directly related to the bugs.

Deindexing Bug — April 5, 2019

Confirmed

Google confirmed a bug that dropped pages from the search index around the weekend of April 5th. Moz data suggested drops on April 5th and 7th, with about 4% of stable URLs falling off of page one. Most sites recovered soon after.

March 2019 Core Update — March 12, 2019

Confirmed

Google confirmed a “core” update, stating it was the third major core update since they began using that label. MozCast hit a peak of 101.2°F, a bit below March 1st temperatures. No specific details were given about the nature of the update.

19-result SERPs — March 1, 2019

Unconfirmed

For one day, Google showed anomalous page-1 counts, with up to 19 organic results. These appeared to be related to In-depth Articles, which disappeared entirely on March 6. MozCast reached 108.2°F, but it’s unclear how much of this was due to the temporary boost in organic counts.

Unnamed Update — February 6, 2019

Unconfirmed

After a relatively quiet December and January, tracking tools detected heavy ranking flux, with MozCast reaching 103.4°F.