Google Algo Updates and More – A Complete List of Changes that Could Affect Your Site’s Traffic.

googleArticle last updated – April 12, 2016

The following is a complete history of every Google algorithm change that was either confirmed by Google or suspected by those of us who do a lot of traffic drop analysis work.

When I am doing traffic drop audits I am constantly referencing a number of different sources for the dates of significant changes that may affect traffic drops.  Moz has got a great list of Google Algorithm Changes, but there are many other factors that could affect a site’s traffic such as blog networks being deindexed, changes to the image algorithm, and more.  I created this list so that I would have a good reference when doing traffic drop audits.  If you can think of other changes that happened that may affect a site’s traffic, let me know!

2016 2015 2014 2013 2012 Early Panda Updates





  • February 18, 2016 – Google changed the SERP layout to now include four paid ads at the top of the results for many searches and none on the side. This could possibly result in a lower click through rate for some sites that have high organic rankings.
  • February 9, 2016 – Possible changes in the mobile algorithm. Accuranker noted huge fluctuations in mobile rankings. However, not much was reported amongst site owners. Dr. Pete from Moz noted that these changes may be due to more deep linking for Android Apps in the SERPS.
  • February 5, 2016Possible changes in the mobile algorithm. Dr. Pete from Moz noticed a big jump in the number of sites that had the “mobile friendly” tag appearing on the first page of mobile results. Other ranking tools picked this up as well. However, there was not much chatter amongst webmasters. Plus, it appears that this change reverted the next day. This may have been some type of test of a new mobile algorithm change. Dr. Pete from Moz noted that these changes may be due to more deep linking for Android Apps in the SERPS.
  • February 5, 2016 – Google has penalized a large Japanese link network. If you had backlinks coming from this network then you likely saw a drop in rankings.


  • January 17, 2016 – SEOs reported seeing a LOT of changes in the SERPS once again. Google confirmed that this was not Penguin, but rather, more changes to Google’s core algorithm.
  • January 8-10, 2016 (approx) – Changes to Google’s core algorithm. There was no name for this update as Google said it was just one of the many changes they make to their core algorithm all year. However, many webmasters noticed significant changes in rankings at this time. There were quite a few who were convinced this was a Penguin update, but I personally was not seeing any changes on Penguin hit sites that I monitor. Others were thinking this could be Panda. But ultimately it was an overall change to the core algorithm. At this point there is no specific advice for recovery other than to continue to improve the overall quality of your site.


  • December 17, 2015  – Google announced that they will be indexing https by default from now on.
  • December 16, 2015 – Possible Quality/Phantom tremor. (Note – These “algo changes” are hard to pinpoint. These dates are ones on which a lot of people reported significant changes in rankings. Glenn Gabe noted that many sites that saw ranking changes were ones that were also affected by Google’s Quality (Phantom) Update. Instead of naming these “Possible Quality/Phantom tremors” I could also call them, “unknown algorithm changes”.
  • December 14, 2015 – You may notice an “update” label in Google Search Console Analytics data. This does not actually represent a Google update, but rather a change in the way that Google displays impressions and clicks for websites and apps.
  • December 12, 2015 – Possible Quality/Phantom tremor.
  • December 10, 2015 – Possible Quality/Phantom tremor.
  • December 4, 2015 – Possible Quality/Phantom tremor.


  • November 28, 2015 – Possible Quality/Phantom tremor.
  • November 19, 2015 – Possibly an update to the Quality/Phantom algorithm. Many webmasters noticed ranking changes at this time although it is not obvious whether this was a Panda related change. Glenn Gabe noticed that many sites with quality issues were affected.
  • November 2, 2015 – Possible Panda tremor. I personally saw several sites with Panda issues either increase or decrease on this date. However, other SEOs who do Panda work did not notice changes. This “new Panda” may make it difficult to determine when Panda related changes are happening.
  • November 1, 2015 – Google’s app interstitial penalty goes live. Mobile friendly pages that show a large interstitial app will no longer get the mobile friendly label. This could cause a drop in mobile traffic.


  • October 14/15, 2015 Possible Panda movement – Some wondered if they were seeing more “zombie” traffic being reported. (Zombie traffic is useless non-legitimate traffic that Google can occasionally send). However, several sites reported Panda improvements or hits on this date. Still, many sites that are awaiting Panda recovery have not seen any movement at all.
  • October 7, 2015 (approx)Possible unannounced algo shift. While nothing official was announced on this day, many webmasters saw a change in rankings. Some speculated that this was Google testing Penguin. Others thought it was a continuation of the long rollout of Panda that started in July. Personally, I saw some small increases in a couple of sites that had both Penguin and Panda issues.
  • October 5, 2015 (approx) – Google announced that they have released a new algorithm to deal with how they display hacked sites in the search engine results. This change affects 5% of queries, which is a fairly big thing. If you noticed a drop on or around this date, you may want to investigate for evidence of hacking. (Quick tip…try doing Google searches like this – viagra | cialis | ugg | kors to see if there are pages on your site that are hosting hacked content.
  • October 1-14 (approx) – Do you run a Wix website? For some reason Google has had trouble crawling these and they have been dropping out of Google’s index. Google became aware of the problem around October 13 and is working to fix it. This change also affected other websites that use AJAX crawling with an escaped fragment.


  • September 16, 2015Possible Panda tremor. Glenn Gabe noticed several sites seeing significant Panda hits/recoveries on this date. Still, most sites awaiting Panda recovery saw nothing.
  • September 16, 2015 (approx) – iOS 9 was released along with a feature to allow users to block ads. It appears that this feature also blocks scripts that track analytics. If you see a drop in Google Analytics traffic around this time, compare your mobile traffic to desktop to see if there is a big difference. It may be that you’re not actually seeing a traffic drop, but that visits from iPhones and iPads are no longer being tracked.
  • September 15, 2015 Google image referral bug – This bug affected images outside of the US. Sites that see a lot of referrals from Google images may have a temporary drop on this day. It was fixed as of September 16.
  • September 9, 2015Possible Panda tremor. I didn’t personally see much Panda action on this day, but Glenn Gabe noticed some sites seeing Panda related movement.
  • September 2, 2015 – Possible Panda tremor.


  • August 31, 2015Possible Panda action – Panda 4.2 started rolling out in mid July but very few people reported changes. Around August 31, a few sites noticed some Panda related movement. For example, which had seen an increase in July saw a slight decrease on August 31. Still, most SEOs who work with Panda hit sites saw very little movement on either of these dates.
  • August 6, 2015 – There were big changes in how Google displays local listings. It appears that in most places where Google would previously display 7 local listings, they are now only displaying 3. This is not just a US change, but appears to be international. While some sites will see a drop in traffic because they were previously in the lower half of the 7-pack, others may see an increase in traffic because Google is no longer displaying the full address which may cause more people to click through to the website.
  • August 1, 2015 (approximate date)Unannounced algo update. Many people saw dramatic changes in rankings. I had several Penguin hit clients who saw significant improvements at this time, but Gary Illyes from Google told me that this was not Penguin related. It appears that most people who saw changes at this time had those changes revert a few days later.





  • Last week of April: Possible changes to the Google news algorithm.
  • April 29, 2015 – May 1, 2015  – The Quality Update, also known as Phantom 2. This was a fairly large update, which was quite similar to Panda. The focus appears to be on on-site quality, but Google has not given much instruction on recovery other than a vague, “Improve your quality”.
  • April 25, 2015 (date approximate) – Possible unannounced algorithm change. Many people saw ranking changes and the tools like Mozcast and Algoroo reported changes that appeared to be unrelated to the mobile friendly algorithm.
  • April 22, 2015 (or possibly starting within the following week) – The mobile friendly algorithm was launched. This algorithm gives a boost to sites that Google deems mobile friendly. It only affects mobile rankings and not desktop.
  • Sometime in April (probably): Google likely launched a change to the doorway page algorithm that punished sites with doorway pages. However, no one in the SEO world really noticed much change so it’s hard to say exactly when this happened.


  • March 25, 2015 – Possible unannounced algorithm change. Some people suspected that this was a test of Panda. John Mueller from Google commented that these changes and those seen around March 18-20 were likely just normal algorithm fluctuations.
  • March 18-20, 2015 (dates approximate) – Possible unannounced algorithm change. Many people saw ranking changes, but this was not Panda or Penguin.
  • March 10, 2015 – Google know showing drink recipes in the knowledge snippets. This might affect some recipe sites.


  • February 19, 2015 – A bug causes “This site may be hacked” messages to appear for a large number of sites, resulting in massive temporary traffic drops.
  • February 4, 2015 – Possible unannounced algorithm update. This was not Panda or Penguin. Glenn Gabe noticed that many of the sites that were affected by this change had quality issues, however.
  • February 4, 2015 – Google launched a mortgage calculator. This won’t affect traffic for most sites.



  • December 22, 2014 (+ a few days for rollout) – The Pigeon Algorithm, affecting the local search results rolled out to English speaking countries outside of the US such as Canada, Australia and the UK.
  • December 5-6, 2014Penguin fluctuations.
  • December 2, 2014 – Possible Penguin refresh. This was likely a continuation of Penguin 3.0 that started on October 17. Many sites saw further hits or increases on December 2, but most of these appeared to be short lived.


  • November 27, 2014 – Confirmed refresh of Penguin. This was a continuation of Penguin 3.0 that started on October 17. This was also Thanksgiving weekend, so changes in traffic around this time can be difficult to interpret.
  • November 24, 2014 – A large Polish link network was taken down by Google.
  • November 14, 2014Google drops the carousel for local results. This likely didn’t result in much traffic fluctuation, but could possibly have caused some changes for some small businesses.
  • November 13, 2014 – Possible unannounced algo update. There is a possibility that this was a mild refresh of Penguin. However, I did not see much change in sites I monitor.
  • November 10-11, 2014 – Possible unannounced algo update. This likely was not Panda or Penguin, but many people saw ranking changes.


  • October 24, 2014 – Unannounced Panda refresh. This was not announced by Google but most of us who do Panda work noticed dramatic changes in some Panda hit sites at this time. 6 months later when we were wondering why Panda was no longer refreshing, John Mueller confirmed that the last refresh was at the end of October.
  • October 22, 2014Possible tweaking of the Penguin algorithm.
  • October 21, 2014Google Pirate Update – Aimed at illegal torrent sites and other sites with large amounts of pirated content.
  • October 17, 2014 – Penguin 3.0 refresh. After waiting for an entire year, Penguin finally refreshed on this date. This was not an Update but rather a refresh which means that nothing changed in how Google makes Penguin calculations, but they just re-ran the algorithm. This was a rolling algorithm refresh that had no fixed end. However, most sites that saw changes saw them on October 17-18, October 22, November 27, December 2, 5 or 6. This was supposed to be a refresh that would allow people who had done cleanup work to recover, but many sites that should have recovered, did not.
  • October 9, 2014Possible testing of the Penguin algorithm. This is not confirmed, but I had many people who had sites previously affected by Penguin contact me to say that rankings were up. In most cases these disappeared within 24 hours. If you saw a short spike in traffic on this day it may be that your rankings were part of Google’s testing on Penguin.
  • October 12, 2014Probable Panda Tremor – Many sites that were previously affected by Panda 4.1 in late September saw an increase or decrease in traffic at this time.
  • October 4-6, 2014 (dates approximate) – Possible unannounced update – Many people saw dramatic changes in rankings at this time. Most likely this was a continuation of the slow rollout of Panda.


  • September 29, 2014 – Possible Panda Tremor – People who do a lot of work with Panda sites saw a lot of up and down movement on sites on this day. Some had seen no movement with the initial rollout of Panda 4.1 on September 25.
  • September 25, 2014 (and continuing off and on for 1-2 weeks) – Panda 4.1. This was a slow rollout that apparently took a week or more and may have started a few days prior to September 25.
  • September 21-23, 2014 (dates approximate) – Google gives out many manual penalties to private blog network sites. If you used PBN links to rank, you may have seen a drop at this time.
  • September 16, 2014Google penalizes several Turkish news sites. This is not likely to affect most sites’ traffic.
  • September 5, 2014Probable unannounced Panda refresh. Google did not announce a refresh of Panda on this date, but many people who do work with Panda hit sites noticed significant changes.




  • June 28, 2014 – Possible Unannounced Update – May have been due to a drop in Authorship photos.
  • June 24, 2014Possible Mild Unannounced Update – I debated even including this one as not many sites appeared to be affected but it is possible that Google made some significant algorithmic changes on this date.
  • June 21, 2014Possible Mild Unannounced Update – The tools that track changes in the SERPS all noticed something was going on, but there was not a lot of chatter on search engine forums about changes.
  • June 12, 2014Payday Loans 3 – This update to the Payday Loans algorithm now targets spammy queries as well as spammy sites.


  • May 28, 2014 (approx)Possible unannounced update. Many people thought that this was a Penguin refresh, but Google denied it. Personally, I do not think that this was related to Penguin.
  • May 20, 2014Panda 4.0  – This was a large Panda update that affected many sites. Quite a few sites that were previously hit by Panda saw very dramatic increases in traffic. This was a whole new version of Panda with a new architecture that was apparently much more lenient. My note: Many sites that saw changes with Panda 4.0 started to see changes a few days before the official announcement of Panda 4.0.
  • May 16, 2014 (approx)Payday Loans 2 – Google made the announcement on May 20 that they had released a new version of this spam algorithm that targets spam in competitive niches. You don’t have to be a Payday Loans site to be affected. This caused a lot of confusion as Payday Loans was updated a couple of days before a massive Panda update (Panda 4.0).
  • May 2 & May 7, 2014Possible unannounced update. However, this seemed to revert on May 12. Many big brands saw rankings change around this time.







  • November 27-29, 2013 (dates approximate) – Possible unannounced update. Barry Schwartz reported that a lot of sites were reporting traffic losses, but it was possible that this was just low traffic due to the Thanksgiving holiday.
  • November 14, 2013Unannounced update – Google did not announce an update, but a LOT of websites had their traffic adversely affected on this day.
  • November 1-5, 2013 (dates approximate) – Possible unannounced update.


  • October 16, 2013 – Possible unannounced update.  It was speculated that this was related to Penguin, but we have no confirmation of this.
  • October 4, 2013Penguin 2.1 update – This Penguin update affected a lot of sites.



  • August 20, 2013Unannounced update – May have been Hummingbird
  • August 6, 2013 – Google announces In Depth Articles.  This likely did not have a drastic effect on the traffic of most sites.  But, if you notice a change on this date, it may be that some of your articles were either pushed up or down in the SERPS depending on whether Google thought they were worthy of the “In Depth Article” label.
  • August 1, 2013Google Analytics Reporting bug – For many, but not all Google analytics users, GA just stopped reporting traffic.  I’m not sure if this has been corrected or not.  But, if you see a sharp dip on Aug 1, it’s probably just a reporting error.


  • July 26-29, 2013 (dates approximate) – Possible Unannounced update.  The general consensus was that this probably was not a Panda or Penguin update.  It is even debatable whether anything actually happened.
  • July 19, 2013 – The Knowledge Graph expanded significantly.
  • July 12-18, 2013 (dates approximate)- Confirmed Panda update. This was the first of the new “softer” Panda updates.


  • June 27, 2013 (and surrounding dates) – “Multi-Week” Algorithm update. There were many ranking fluctuations during the last week in June.
  • June 19, 2013 – Possible unannounced update.  However, if you read the comments, many people thought this was a Google Analytics bug.
  • June 14, 2013 – Google changes the image carousel in image search. This *might* affect image search queries.
  • June 11, 2013Payday Loans algorithm rolls out.  This algorithm doesn’t just affect payday loans sites, but any site that has the potential for super spammy SERPS.
  • June 5, 2013Unannounced update
  • June 5, 2013Knowledge Graph adds nutrition info.  This won’t affect most sites, but certainly can cause a drop in rankings for calorie counting/fitness/recipe sites.



  • April 6, 2013Potential unannounced update – Although, if you read the comments, it sounds like perhaps there was a temporary glitch with Google analytics


  • March 27, 2013Google Updates its Quality Guidelines for News – “If a site mixes news content with affiliate, promotional, advertorial, or marketing materials (for your company or another party), we strongly recommend that you separate non-news content on a different host or directory, block it from being crawled with robots.txt, or create a Google News Sitemap for your news articles only. Otherwise, if we learn of promotional content mixed with news content, we may exclude your entire publication from Google News.”
  • March 15, 2013Google announces no more regular Panda updates – From this point on, Google will no longer be announcing Panda updates.  They will gradually roll out with the regular algorithm changes.
  • March 14, 2013 Panda Refresh? – Google said that they would release Panda this weekend.  No official date was given, but most SEO’s believe it was around March 14…possibly March 13.
  • March 7, 2013Google Penalizes SAPE links – A Russian link network, SAPE links is penalized so that links coming from this network are likely worthless.


  • February 22, 2013News Websites Penalized – Google reduced the PageRank of many UK news websites to zero because they have been selling links in the form of advertorials



  • December 21, 2012 Panda Refresh
  • December 13, 2012Safe Search Changes – Google updated the way that Safe Search works so that it is now more strict on explicit content.
  • December 10, 2012Unannounced update? – No official update was announced, but many webmasters were compaining about traffic changes at this time.
  • December 4, 2012 – Google expands the Knowledge graph.




  • September 28, 2012EMD update – This update demoted low quality exact match domains.
  • September 27, 2012Panda update – This was a major update that affected a lot of sites.
  • September 18, 2012Panda refresh
  • September 14, 2012Diversification update – This was a small update intended to diversify search results.







Earlier Panda refreshes/updates:

  • February 27, 2012
  • January 18, 2012
  • November 18, 2011
  • September 28, 2011
  • August 12, 2011
  • July 23, 2011
  • June 21, 2011
  • May 9, 2011
  • April 11, 2011
  • February 23, 2011(initial rollout of Panda)


Did I miss any important algo shifts?  Please let me know and I’ll give you credit as it is added to the list.

  1. “It may be that you’re not actually seeing a traffic drop, but that visits from iPhones and iPads are no longer being tracked.”

    This looks to be the case on several sites I manage in GA. Well done, thanks for explaining the drop in traffic we’d seen.

  2. Wow Marie – great job, now this is something I would (and probably will) link to. Excellent resource. I really like Moz’s history but to be honest this one is much easier to quickly scan for some reason. 10/10

    • Thanks Patrick! A lot of hours went into creating this. I had a list started in a Google doc which I used to help me when I was doing site audits…and then figured I’d pretty it up for others to use as well.

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Marie Haynes is the founder of HIS Web Marketing, formerly at In 2015, she rebranded the company to Marie Haynes Consulting Inc.
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