Social Signals - December 2010
Google and Bing confirmed that they use social signals in determining ranking, including data from Twitter and Facebook. Matt Cutts confirmed that this was a relatively new development for Google, although many SEOs had long suspected it would happen.
Negative Reviews - December 2010
After an expose in the New York Times about how e-commerce site DecorMyEyes was ranking based on negative reviews, Google made a rare move and reactively adjusted the algorithm to target sites using similar tactics.
A Bully Finds a Pulpit on the Web (NY Times)
Instant Previews - November 2010
A magnifying glass icon appeared on Google search results, allowing search visitors to quickly view a preview of landing pages directly from SERPs. This signaled a renewed focus for Google on landing page quality, design, and usability.
Google Instant - September 2010
Expanding on Google Suggest, Google Instant launched, displaying search results as a query was being typed. SEOs everywhere nearly spontaneously combusted, only to realize that the impact was ultimately fairly small.
About Google Instant (Google)
Brand Update - August 2010
Although not a traditional algorithm update, Google started allowing the same domain to appear multiple times on a SERP. Previously, domains were limited to 1-2 listings, or 1 listing with indented results.
Caffeine (Rollout) - June 2010
After months of testing, Google finished rolling out the Caffeine infrastructure. Caffeine not only boosted Google's raw speed, but integrated crawling and indexation much more tightly, resulting in (according to Google) a 50% fresher index.
Our new search index: Caffeine (Google)
May Day - May 2010
In late April and early May, webmasters noticed 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.
Video: Google's Matt Cutts On May Day Update (SERoundtable)
Google Places - April 2010
Although "Places" pages were rolled out in September of 2009, they were originally only a part of Google Maps. The official launch of Google Places re-branded the Local Business Center, integrated Places pages more closely with local search results, and added a number of features, including new local advertising options.
Introducing Google Places (Google)
