Awesome List of SEO Articles & Resources
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Search Engine
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Behavior
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Google Back Button Behavior Triggers People Also Search For Carousel
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Google
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[Google Algorithm Change History] (https://moz.com/google-algorithm-change)
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Penguin
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2016 -Oct 6 - Penguin 4.0 Phase 2: The second phase of Penguin 4.0 was the reversal of all previous Penguin penalties. This seemed to happen after the new code rolled out, and may have taken as long as two weeks. Post-Penguin activity had one final peak on October 6th (116°), but it is unclear whether this was Penguin or a new update. Algorithm temperatures finally started to drop after October 6th. -Sep 27 - Penguin 4.0 Phase 1: The first phase of Penguin 4.0, which probably launched around September 22-23, was the rollout of the new, "gentler" Penguin algorithm, which devalues bad links instead of penalizing sites. The exact timeline is unconfirmed, but we believe this rollout took at least a few days to fully update, and may have corresponded to an algorithm temperature spike (113°) on September 27th. -Sep 23 - Penguin 4.0 Announcement: After almost two years of waiting, Google finally announced a major Penguin update. They suggested the new Penguin is now real-time and baked into the "core" algorithm. Initial impact assessments were small, but it was later revealed that the Penguin 4.0 rollout was unusually long and multi-phase (see September 27th and October 6th). -Sep 13 - Image/Universal Drop: MozCast recorded a nearly-record 111° temperature and a 50% drop in SERPs with image (universal/vertical) results. The universal result shake-up opened up an organic position on page 1, causing substantial ranking shifts, but it's likely that this was part of a much larger update.
-Jan 8 - Unnamed Update: 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.
-2014 -Dec 20 - Penguin Everflux: A Google representative said that Penguin had shifted to continous 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). -Oct 17 - Penguin 3.0: Update appreared to be smaller than expected (less than 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".
-2013 -Dec 17 - Unnamed Update: Almost all global flux trackers registered historically high activity. Google would not confirm an update, suggesting that they avoid updates near the holidays. MozCost also registed a rise in some Partial-Match Domains (PMDs), but the patterns were unclear. -Oct 4 - Penguin 2.1 (#5): Data update(primarily) and not a major change to the Penguin algorithm. The overall impact seemed to be moderate, although some webmasters reported being hit hard. -May 22 - Penguin 2.0 (#4): Moderate impact. The exact nature of the changes were unclear, but some evidence suggested that Penguin 2.0 was more finely targeted to the page level. -May 21 - Domain Crowding: Update to control domain crowding/diversity deep in the SERPs(pages 2+).
-2012 -Oct 5 - Penguin #3: Impacting "0.3% of queries". Penguin update numbering was rebooted, similar to Panda - this was the 3rd Penguin release. -May 25 - Penguin 1.1: This confirmed that Penguin data was being processed outside of the main search. -May 4 - April 52 Pack: Google published details of 52 updates in April, including changes that were tied to the "Penguin"update. Other highlights included a 15% larger "base" index, improved pagination handling and a number of updates to sitelinks.
- Panda
-2014 -Jul 17 - Panda 4.2 (#28): 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. -Sep 23 - Panda 4.1 (#27): 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. -May 19 - Panda 4.0 (#26): Google confirmed a major Panda update that likely included both an algorithm update and a data refresh. Officially, about 7.5% of English-language queries were affected. While Matt Cutts said it began rolling out on 5/20, our data strongly suggests it started earlier. -Mar 24 - Unnamed Update: Major algorithm flux trackers and webmaster chatter spiked around 3/24-3/25, and some speculated that the new, "softer" Panda update had arrived. Many sites reported ranking changes, but this update was never confirmed by Google.
-2013 -Jul 18 - Panda Recovery : Google confirmed a Panda update, but it was unclear whether this was one of the 10-day rolling updates or something new. The implication was that this was algorithmic and may have "softened" some previous Panda penalties. -Jun 11 - Panda Dance: While not an actual Panda update, Matt Cutts made an important clarification at SMX Advanced, suggesting that Panda was still updating monthly, but each update rolled out over about 10 days. This was not the "everflux" many people had expected after Panda #25. -Mar 14 - Panda #25: Matt Cutts pre-announced a Panda update at SMX West, and suggested it would be the last update before Panda was integrated into the core algorithm. The exact date was unconfirmed, but MozCast data suggests 3/13-3/14. -Jan 22 - Panda #24: Google announced its first official update of 2013, claiming 1.2% of queries affected. This did not seem related to talk of an update around 1/17-18 (which Google did not confirm).
-2012 -Dec 21 - Panda #23 : Right before the Christmas holiday, Google rolled out another Panda update. They officially called it a "refresh", impacting 1.3% of English queries. This was a slightly higher impact than Pandas #21 and #22. -Nov 21 - Panda #22: After some mixed signals, Google confirmed the 22nd Panda update, which appears to have been data-only. This came on the heels of a larger, but unnamed update around November 19th. -Nov 5 - Panda #21: Google rolled out their 21st Panda update, roughly 5-1/2 weeks after Panda #20. This update was reported to be smaller, officially impacting 1.1% of English queries. -Oct 9 - Page Layout #2 : Google announced an update to its original page layout algorithm change back in January, which targeted pages with too many ads above the fold. It's unclear whether this was an algorithm change or a Panda-style data refresh. -Sep 27 - Panda #20: Overlapping the EMD update, a fairly major Panda update (algo + data) rolled out, officially affecting 2.4% of queries. As the 3.X series was getting odd, industry sources opted to start naming Panda updates in order (this was the 20th). -Sep 18 - Panda 3.9.2 (#19): Google rolled out another Panda refresh, which appears to have been data-only. Ranking flux was moderate but not on par with a large-scale algorithm update. -Aug 20 - Panda 3.9.1 (#18): Google rolled out yet another Panda data update, but the impact seemed to be fairly small. Since the Panda 3.0 series ran out of numbers at 3.9, the new update was dubbed 3.9.1. -Jun 24 - Panda 3.9 (#17: A month after Panda 3.8, Google rolled out a new Panda update. Rankings fluctuated for 5-6 days, although no single day was high enough to stand out. Google claimed ~1% of queries were impacted. -Jun 25 - Panda 3.8 (#16): Google rolled out another Panda data refresh, but this appeared to be data only (no algorithm changes) and had a much smaller impact than Panda 3.7. -Jun 8 - Panda 3.7 (#15): Google rolled out yet another Panda data update, claiming that less than 1% of queries were affect. Ranking fluctuation data suggested that the impact was substantially higher than previous Panda updates (3.5, 3.6). -Apr 27 - Panda 3.6 (#14): Barely a week after Panda 3.5, Google rolled out yet another Panda data update. The implications of this update were unclear, and it seemed that the impact was relatively small. -Apr 19 - Panda 3.5 (#13): In the middle of a busy week for the algorthim, Google quietly rolled out a Panda data update. A mix of changes made the impact difficult to measure, but this appears to have been a fairly routine update with minimal impact. -Mar 23 - Panda 3.4 (#12): Google announced another Panda update, this time via Twitter as the update was rolling out. Their public statements estimated that Panda 3.4 impacted about 1.6% of search results. -Feb 27 - Panda 3.3 (#11): Google rolled out another post-"flux" Panda update, which appeared to be relatively minor. This came just 3 days after the 1-year anniversary of Panda, an unprecedented lifespan for a named update. -Feb 3 - February 17-Pack: Google released another round of "search quality highlights" (17 in all). Many related to speed, freshness, and spell-checking, but one major announcement was tighter integration of Panda into the main search index. -Jan 19 - Ads Above The Fold: Google updated their page layout algorithms to devalue sites with too much ad-space above the "fold". It was previously suspected that a similar factor was in play in Panda. The update had no official name, although it was referenced as "Top Heavy" by some SEOs. -Jan 18 - Panda 3.2 (#10): Google confirmed a Panda data update, although suggested that the algorithm hadn't changed. It was unclear how this fit into the "Panda Flux" scheme of more frequent data updates.
-2011 -Nov 18 - Panda 3.1 (#9): After Panda 2.5, Google entered a period of "Panda Flux" where updates started to happen more frequently and were relatively minor. Some industry analysts called the 11/18 update 3.1, even though there was no official 3.0. For the purposes of this history, we will discontinue numbering Panda updates except for very high-impact changes. -Oct 5 - Panda "Flux" (#8): Matt Cutts tweeted: "expect some Panda-related flux in the next few weeks" and gave a figure of "~2%". Other minor Panda updates occurred on 10/3, 10/13, and 11/18 -Sep 28 - Panda 2.5 (#7): After more than month, Google rolled out another Panda update. Specific details of what changed were unclear, but some sites reported large-scale losses. -Aug 12 - Panda 2.4 (#6): Google rolled Panda out internationally, both for English-language queries globally and non-English queries except for Chinese, Japanese, and Korean. Google reported that this impacted 6-9% of queries in affected countries. -Jul 23 - Panda 2.3 (#5): Webmaster chatter suggested that Google rolled out yet another update. It was unclear whether new factors were introduced, or this was simply an update to the Panda data and ranking factors. -Jun 21 - Panda 2.2(#4): Google continued to update Panda-impacted sites and data, and version 2.2 was officially acknowledged. Panda updates occurred separately from the main index and not in real-time, reminiscent of early Google Dance updates. -May 9 - Panda 2.1(#3): Initially dubbed “Panda 3.0”, Google appeared to roll out yet another round of changes. These changes weren’t discussed in detail by Google and seemed to be relatively minor. -Apr 11 - Panda 2.0(#2): Google rolled out the Panda update to all English queries worldwide (not limited to English-speaking countries). New signals were also integrated, including data about sites users blocked via the SERPs directly or the Chrome browser. -Feb 23 - Panda/Farmer: A major algorithm update hit sites hard, affecting up to 12% of search results (a number that came directly from Google). Panda seemed to crack down on thin content, content farms, sites with high ad-to-content ratios, and a number of other quality issues. Panda rolled out over at least a couple of months, hitting Europe in April 2011. -Jan 28 - Attribution Update: In response to high-profile spam cases, Google rolled out an update to help better sort out content attribution and stop scrapers. According to Matt Cutts, this affected about 2% of queries. It was a clear precursor to the Panda updates. -Jan - Overstock.com Penalty: In a rare turn of events, a public outing of shady SEO practices by Overstock.com resulted in a very public Google penalty. JCPenney was hit with a penalty in February for similar bad behavior. Both situations represented a shift in Google's attitude and foreshadowed the Panda update.
-2010 -May - May Day: Significant drops in their long-tail traffic. Matt Cutts later confirmed that May Day was an algorithm change impacting the long-tail. Sites with large-scale thin content seemed to be hit especially hard, foreshadowing the Panda update.
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