30 - (Search quality Highlights - 2012Google announced 30 changes over the previous month, including image search landing-page quality detection, more relevant site-links, more rich snippets, and related-query improvements. The line between an "algo update" and a "feature" got a bit more blurred. For more refer the original source below.
30 search quality highlights - with codenames! (Google)
Google Announces “Megasitelinks,” Image Search Improvements & Better Byline Dates (SEL)
Panda 3.2 - January 2012
Google confirmed Panda 3.2 data update, although suggested that the algorithm hadn't changed. Only data refresh has been done a week ago.
Page layout algorithm - Ads Above The Fold - January 2012
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.
Panda 3.3 - February 2012
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.
Search Quality Video - March 12, 2012
This wasn't an algorithm update, but Google published a rare peek into a search quality meeting. For anyone interested in the algorithm, the video provides a lot of context to both Google's process and their priorities. It's also a chance to see Amit Singhal in action.
Panda 3.4 - March 23, 2012
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.
Parked Domain Bug — April , 2012
After a number of webmasters reported ranking shuffles, Google confirmed that a data error had caused some domains to be mistakenly treated as parked domains (and thereby devalued). This was not an intentional algorithm change.
Panda 3.5 - April , 2012
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.
Penguin Update - April , 2012
After weeks of speculation about an "Over-optimization penalty", Google finally rolled out the "Webspam Update", which was soon after dubbed "Penguin." Penguin adjusted a number of spam factors, including keyword stuffing, and impacted an estimated 3.1% of English queries.
Panda 3.6 - April , 2012
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.
Google : list of Quality Update till April - May, 2012
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.
Knowledge Graph - May 16, 2012
In a major step toward semantic search, Google started rolling out "Knowledge Graph", a SERP-integrated display providing supplemental object about certain people, places, and things. Expect to see "knowledge panels" appear on more and more SERPs over time. Also, Danny Sullivan's favorite Trek is ST:Voyager?!
Penguin 1.1 (#2) - May , 2012
Google rolled out its first targeted data update after the "Penguin" algorithm update. This confirmed that Penguin data was being processed outside of the main search index, much like Panda data.
Panda 3.7 (#15) — June , 2012
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).
Panda 3.8 (#16) — June , 2012
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.
Link Warnings — July , 2012
In a repeat of March/April, Google sent out a large number of unnatural link warnings via Google Webmaster Tools. In a complete turn-around, they then announced that these new warnings may not actually represent a serious problem.
Panda 3.9 (#17) — July, 2012
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.
DMCA Penalty ("Pirate") — August, 2012Google announced that they would start penalizing sites with repeat copyright violations, probably via DMCA takedown requests. Timing was stated as "starting next week" (8/13?).
An update to our search algorithms (Google)
The Emanuel Update: Google Will Penalize Sites Repeatedly Accused Of Copyright Infringement (SEL)
Panda 3.9.1 (#18) — August , 2012Google 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.
Confirmed: Google Panda 3.9.1 Update (SER)
Google Panda Refresh On August 19th: Version 3.9.1 (SEL)
Panda 3.9.2 (#19) — September , 2012Google 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.
Google Rolls Out Panda 3.9.2 Refresh (SER)
Panda Update 3.92 Rolling Out (Or Is It Panda 20 Time?) (SEL)
Exact-Match Domain (EMD) Update — September, 2012Google announced a change in the way it was handling exact-match domains (EMDs). This led to large-scale devaluation, reducing the presence of EMDs in the MozCast data set by over 10%. Official word is that this change impacted 0.6% of queries (by volume).
Google's EMD Algo Update - Early Data (SEOmoz)
The EMD Update: Google Issues “Weather Report” Of Crack Down On Low Quality Exact Match Domains (SEL)
Penguin #3 — October 5, 2012After suggesting the next Penguin update would be major, Google released a minor Penguin data update, impacting "0.3% of queries". Penguin update numbering was rebooted, similar to Panda - this was the 3rd Penguin release.
Google Penguin Update 3 Released, Impacts 0.3% Of English-Language Queries (SEL)
Google Released 3rd Penguin Update: Not Jarring Or Jolting (SER)
Page Layout #2 — October 9, 2012Google 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.
It’s “Top Heavy 2? As Google Rolls Out Update To Its Page Layout Algorithm (SEL)
Google Page Layout Algorithm Officially Updated (SER)
Panda #21 — November 5, 2012Google 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.
Google Releases Panda Update 21, Impacts 1.1% Of US Queries In English (SEL)
Official: Google Panda Refresh On November 5th (Version 21) (SER)
Panda #22 — November 21, 2012After 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.
Official Google Panda #22 Update: November 21 (SER)
Confirmed: Google Panda Refresh #22 On November 21st; 0.8% Of Queries Impacted (SEL)
Knowledge Graph Expansion — December 4, 2012Google added Knowledge Graph functionality to non-English queries, including Spanish, French, German, Portuguese, Japanese, Russian, and Italian. This update was "more than just translation" and added enhanced KG capabilities.
Get smarter answers from the Knowledge Graph from Português to Japanese to Russian (Google)
Google’s Knowledge Graph Expands To More Languages, Including Italian, French, Japanese And Russian (TechCrunch)
Panda #23 — December 21, 2012Right 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.
Confirmed: A Panda Refresh, Version #23 (SER)
Check out : Google Algorithm Change History 2013