December 10-Pack - December 1, 2011
Google outlined a second set of 10 updates, announcing that these posts would come every month. Updates included related query refinements, parked domain detection, blog search freshness, and image search freshness. The exact dates of each update were not provided.
Panda 3.1 - November 18, 2011
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.
10-Pack of Updates - November 14, 2011
This one was a bit unusual. In a bid to be more transparent, Matt Cutts released a post with 10 recent algorithm updates. It's not clear what the timeline was, and most were small updates, but it did signal a shift in how Google communicates algorithm changes.
Ten recent algorithm changes (Google)
Freshness Update - November 3, 2011
Google announced that an algorithm change rewarding freshness would impact up to 35% of queries (almost 3X the publicly stated impact of Panda 1.0). This update primarly affected time-sensitive results, but signalled a much stronger focus on recent content.
Query Encryption - October 18, 2011
Google announced they would be encrypting search queries, for privacy reasons. Unfortunately, this disrupted organic keyword referral data, returning "(not provided)" for some organic traffic. This number increased in the weeks following the launch.
Making search more secure (Google)
Panda "Flux" - October 5, 2011
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.
Panda 2.5 - September 28, 2011
After more than month, Google rolled out another Panda update. Specific details of what changed were unclear, but some sites reported large-scale losses.
516 Algo Updates - September 21, 2011
This wasn't an update, but it was an amazing revelation. Google CEO Eric Schmidt told Congress that Google made 516 updates in 2010. The real shocker? They tested over 13,000 updates.
Pagination Elements - September 15, 2011
To help fix crawl and duplication problems created by pagination, Google introduced the rel="next" and rel="prev" link attributes. Google also announced that they had improved automatic consolidation and canonicalization for "View All" pages.
Expanded Sitelinks - August 16, 2011
After experimenting for a while, Google officially rolled out expanded site-links, most often for brand queries. At first, these were 12-packs, but Google appeared to limit the expanded site-links to 6 shortly after the roll-out.
Panda Goes Global (2.4) - August 12, 2011
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.
Panda 2.3 - July 23, 2011
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.
A Holistic Look at Panda with Vanessa Fox (Stone Temple)
Google+ - June 28, 2011
After a number of social media failures, Google launched a serious attack on Facebook with Google+. Google+ revolved around circles for sharing content, and was tightly integrated into products like Gmail. Early adopters were quick to jump on board, and within 2 weeks Google+ reached 10M users.
Panda 2.2 - June 21, 2011
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.
Schema.org - June 2, 2011
Google, Yahoo and Microsoft jointly announced support for a consolidated approach to structured data. They also created a number of new "schemas", in an apparent bid to move toward even richer search results.
Google, Bing & Yahoo Unite To Make Search Listings Richer Through Structured Data (SEL) What is Schema.org? (Schema.org)
Panda 2.1 - May 9, 2011
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.
Google Panda 3.0 (SERoundtable)
Panda 2.0 - April 11, 2011
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.
Panda 2.0: Google Rolls Out Panda Update Internationally & Incorporates Searcher Blocking Data (SEL)
The +1 Button - March 30, 2011
Responding to competition by major social sites, including Facebook and Twitter, Google launched the +1 button (directly next to results links). Clicking [+1] allowed users to influence search results within their social circle, across both organic and paid results.
Recommendations when you want them (Google)
Panda/Farmer - February 23, 2011
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.
Attribution Update - January 28, 2011
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.
Algorithm Change Launched (Matt Cutts)
Latest Google Algorithm change (Search News Central)
Overstock.com Penalty - January 2011
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.