Bobs SEO announced that Google has released two major updates to its algorithms in recent years. The first was called Panda and this was released in February 2011. Panda’s objective was to reduce the number of lower quality sites, for example sites with only a single page or just a few pages, and push higher quality sites nearer to the top of the SERPs. In doing so, Google were able to clear up spam caused by ‘content farms’ that released both low quality and duplicate content.
Many sites prior to 2011 had been using spammy, Black Hat techniques (e.g . keyword stuffing the page and creating thousands of backlinks through software tools) to rank ‘thin sites’ near the top of the SERPs and cash in through advertising, e.g. with Google Adsense. Since 2011, there have been numerous updates to Panda. The 24th version (Panda #24) arrived on January 22, 2013. In 2013 there were an additional 3 updates to Panda: Panda #25 on March 14, 2013 and Panda Dance on June 11 , 2013. On July 18, 2013 came Panda Recovery.
The most recent Panda update was released on May 20, 2014 and was officially named by Google as Panda 4.0 – meaning that most of the previous updates were iterations upon the major Panda updates. Check out their SEO blog to learn more about it.