Google Algorithm Change History
Each year, Google changes its search algorithm around 500–600 times. While most of these changes are minor, Google occasionally rolls out a "major" algorithmic update (such as Google Panda and Google Penguin) that affects search results in significant ways.
For search marketers, knowing the dates of these Google updates can help explain changes in rankings and organic website traffic and ultimately improve search engine optimization. Below, we’ve listed the major algorithmic changes that have had the biggest impact on search.
2016 Updates
Mobile-friendly 2 — May 12, 2016
Just more than a year after the original "mobile friendly" update, Google rolled out another ranking signal boost to benefit mobile-friendly sites on mobile search. Since the majority of sites we track are already mobile-friendly, it's likely the impact of the latest update was small.
Google’s mobile-friendly algorithm boost has rolled out (SEL)
Continuing to make the web more mobile friendly (Google)


Unnamed Major Update — May 10, 2016
MozCast and other Google weather trackers showed a historically rare week-long pattern of algorithm activity, including a 97-degree spike. Google would not confirm this update, and no explanation is currently available.
Google Dismisses Any Recent Major Algorithm Update (SER)

AdWords Shake-up — February 23, 2016
Google made major changes to AdWords, removing right-column ads entirely and rolling out 4-ad top blocks on many commercial searches. While this was a paid search update, it had significant implications for CTR for both paid and organic results, especially on competitive keywords.
Four Ads on Top: The Wait Is Over (Moz)
Google AdWords Switching to 4 Ads on Top, None on Sidebar (SEM Post)

Unnamed Update — January 8, 2016
Multiple tracking tools (including MozCast) reported historically-large rankings movement, which Google later confirmed as a "core algo update". Google officially said that this was not a Penguin update, but details remain sketchy.
Google Confirms: Core Search Ranking Update Took Place But Not Penguin Related (SER)
2015 Updates
RankBrain* — October 26, 2015
Google made a major announcement, revealing that machine learning had been a part of the algorithm for months, contributing to the 3rd most influential ranking factor. *Note: This is an announcement date - we believe the actual launch was closer to spring 2015.
Google Turning Its Lucrative Web Search Over to AI Machines (Bloomberg)
FAQ: All About The New Google RankBrain Algorithm (SEL)

Panda 4.2 (#28) — July 17, 2015
Google announced what was most likely a Panda data refresh, saying that it could take months to fully roll out. The immediate impact was unclear, and there were no clear signs of a major algorithm update.
Google Panda Update: Everything We Know About Panda 4.2 (The SEM Post)
Google Panda 4.2 Is Here (SEL)

The Quality Update — May 3, 2015
After many reports of large-scale ranking changes, originally dubbed "Phantom 2", Google acknowledged a core algorithm change impacting "quality signals". This update seems to have had a broad impact, but Google didn't reveal any specifics about the nature of the signals involved.
The Quality Update: Google Confirms Changing How Quality Is Assessed, Resulting In Rankings Shake-Up (SEL)
Google's 'phantom' algorithm update hits websites (CNBC)

Mobile Update AKA "Mobilegeddon" — April 22, 2015
In a rare move, Google pre-announced an algorithm update, telling us that mobile rankings would differ for mobile-friendly sites starting on April 21st. The impact of this update was, in the short-term, much smaller than expected, and our data showed that algorithm flux peaked on April 22nd.
Finding more mobile-friendly search results (Google)
7 Days After Mobilegeddon: How Far Did the Sky Fall? (Moz)

Unnamed Update — February 4, 2015
Multiple SERP-trackers and many webmasters reported major flux in Google SERPs. Speculation ranged from an e-commerce focused update to a mobile usability update. Google did not officially confirm an update.
Significant Google Search Algorithm Update Yesterday (SER)
Google Brand-eCommerce “Update” causing fluctuations (Searchmetrics)
2014 Updates
Pigeon Expands (UK, CA, AU) — December 22, 2014
Google's major local algorithm update, dubbed "Pigeon", expanded to the United Kingdom, Canada, and Australia. The original update hit the United States in July 2014. The update was confirmed on the 22nd but may have rolled out as early as the 19th.
Google Pigeon Update Rolls Out To UK, Canada & Australia (SEL)
Local Search Results Affected as Google Pigeon Update Hits UK (Strategy Digital)

Penguin Everflux — December 10, 2014
A Google representative said that Penguin had shifted to continuous updates, moving away from infrequent, major updates. While the exact timeline was unclear, this claim seemed to fit ongoing flux after Penguin 3.0 (including unconfirmed claims of a Penguin 3.1).
Google Says Penguin To Shift To “Continuous Updates” (SEL)

Pirate 2.0 — October 21, 2014
More than two years after the original DMCA/"Pirate" update, Google launched another update to combat software and digital media piracy. This update was highly targeted, causing dramatic drops in ranking to a relatively small group of sites.
Google Pirate Update Analysis and Loser List (Searchmetrics)
Google's New Search Downranking Hits Torrent Sites Hard (TorrentFreak)

Penguin 3.0 — October 17, 2014
More than a year after the previous Penguin update (2.1), Google launched a Penguin refresh. This update appeared to be smaller than expected (<1% of US/English queries affected) and was probably data-only (not a new Penguin algorithm). The timing of the update was unclear, especially internationally, and Google claimed it was spread out over "weeks".
Google AutoCorrects: Penguin 3.0 Still Rolling Out & 1% Impact (SER)
Penguin 3.0 Analysis – Penguin Tremors, Recoveries, Fresh Hits, and Crossing Algorithms (GSQi)

"In The News" Box — October 2014
Google made what looked like a display change to News-box results, but later announced that they had expanded news links to a much larger set of potential sites. The presence of news results in SERPs also spiked, and major news sites reported substantial traffic changes.
Google’s “In The News” Box Now Lists More Than Traditional News Sites (SEL)
New Publishers Upset With Google's "In The News" Box (SER)

Panda 4.1 (#27) — September 23, 2014
Google announced a significant Panda update, which included an algorithmic component. They estimated the impact at 3-5% of queries affected. Given the "slow rollout," the exact timing was unclear.
Panda 4.1 — Google’s 27th Panda Update — Is Rolling Out (SEL)
Panda 4.1 Analysis and Findings – Affiliate Marketing, Keyword Stuffing, Security Warnings, and Deception Prevalent (GSQI)

Authorship Removed — August 28, 2014
Following up on the June 28th drop of authorship photos, Google announced that they would be completely removing authorship markup (and would no longer process it). By the next morning, authorship bylines had disappeared from all SERPs.
Official Announcement from John Mueller (Google+)
It’s Over: The Rise & Fall Of Google Authorship For Search Results (SEL)

HTTPS/SSL Update — August 6, 2014
After months of speculation, Google announced that they would be giving preference to secure sites, and that adding encryption would provide a "lightweight" rankings boost. They stressed that this boost would start out small, but implied it might increase if the changed proved to be positive.
HTTPS as a ranking signal (Google)
Google Starts Giving A Ranking Boost To Secure HTTPS/SSL Sites (SEL)

Pigeon — July 24, 2014
Google shook the local SEO world with an update that dramatically altered some local results and modified how they handle and interpret location cues. Google claimed that Pigeon created closer ties between the local algorithm and core algorithm(s).
Google “Pigeon” Updates Local Search Algorithm With Stronger Ties To Web Search Signal (SEL)
Google Updates Local Algo with More Web Based Signals - Turmoil in SERPs (Blumenthals.com)