Google has a long history of famous algorithm updates, search index changes and refreshes.
What is Panda Update ?
Panda update was first released in Feb 2011 and major purpose of this update is to penalized the website with low quality content or duplicate or thin content which was created only for SEO purpose. In May 2014 Panda 4 was release which has hit many major brand sites like ebay, ask.com, biography.com and many other sites.
What is Penguin Update ?
Penguin update was first released in April 2012. This update targeted the websites using black hat seo techniques and using over optimization by violating the search guidelines. Later releases of Penguin update has targeted the websites generating links from low quality sources with keyword reach anchor text.
What is Humming bird update ?
This update was released in August 2013. The purpose of this update was to understand the intent of the user in the query and provide the results best suitable for user. Instead of ranking a page because of keyword density, this update understand the semantics of query, relevancy of content and provide the suitable results.
For example if you search for keyword : “which is best business hotel in hyderabad ?” then humming bird will understand the intent of user and provide the results for “best business hotel in hyderabad” by ignoring the words [which is] and [?] to provide relevant results.
What is EMD update ?
This update was released by Google in Sep 2012 to target low quality websites which used exact match domain name sites. The major sites which hit with the update the long tail domains with keywords. Sites like www.buy-best-laptops-online.com were hit with the update. Even some good sites were hit with this update. Example http://www.pooltables.com has lost the 1st position after EMD Update.
If we use a keyword in domain, Will it hit with EMD filter?
If we use a keyword in the domain along with other words or brand name, we must ensure that we are providing quality of content in the site which is protect from EMD filter.
What is Pigeon Update?
Google have released this algorithm to provide more relevant results in Google Local Results. The algorithm consider other traditional web search signals as crucial factors for local ranking. This algorithm name was coined by “Search Engine Land”.
What is Pirate 2.0 Update ?
This update was released to target the websites which distribute the pirated material like pirated movies, software and other copyright material. Most of the torrent sites, online movie distribution sites were hit with this update.
The best source to see all updates ordered by date: Moz Algorithm Updates