8 major Google algorithm updates, explained

Your ultimate cheat sheet to Google’s algorithmic changes and penalties
1. Panda
Launch date: February 24, 2011
Hazards: Duplicate, plagiarized or thin content; user-generated spam; keyword stuffing

How it works: Panda assigns a so-called “quality score” to web pages; this score is then used as a ranking factor. Initially, Panda was a filter rather than part of Google’s ranking algo, but in January 2016, it was officially incorporated into the core algorithm. Panda rollouts have become more frequent, so both penalties and recoveries now happen faster.
2. Penguin
Launch date: April 24, 2012
Hazards: Spammy or irrelevant links; links with over-optimized anchor text

How it works: Google Penguin’s objective is to down-rank sites whose links it deems manipulative. Since late 2016, Penguin has been part of Google’s core algorithm; unlike Panda, it works in real time.
3. Hummingbird
Launch date: August 22, 2013
Hazards: Keyword stuffing; low-quality content

How it works: Hummingbird helps Google better interpret search queries and provide results that match searcher intent (as opposed to the individual terms within the query). While keywords continue to be important, Hummingbird makes it possible for a page to rank for a query even if it doesn’t contain the exact words the searcher entered. This is achieved with the help of natural language processing that relies on latent semantic indexing, co-occurring terms and synonyms.
4. Pigeon
Launch date: July 24, 2014 (US); December 22, 2014 (UK, Canada, Australia)
Hazards: Poor on- and off-page SEO

How it works: Pigeon affects those searches in which the user’s location plays an important part. The update created closer ties between the local algorithm and the core algorithm: traditional SEO factors are now used to rank local results.
5. Mobile
Launch date: April 21, 2015
Hazards: Lack of a mobile version of the page; poor mobile usability

How it works: Google’s Mobile Update (aka Mobilegeddon) ensures that mobile-friendly pages rank at the top of mobile search, while pages not optimized for mobile are filtered out from the SERPs or seriously down-ranked.
6. RankBrain
Launch date: October 26, 2015
Hazards: Lack of query-specific relevance features; shallow content; poor UX

How it works: RankBrain is part of Google’s Hummingbird algorithm. It is a machine learning system that helps Google understand the meaning behind queries, and serve best-matching search results in response to those queries. Google calls RankBrain the third most important ranking factor. While we don’t know the ins and outs of RankBrain, the general opinion is that it identifies relevance features for web pages ranking for a given query, which are basically query-specific ranking factors.
7. Possum
Launch date: September 1, 2016
Hazards: Tense competition in your target location

How it works: The Possum update ensured that local results vary more depending on the searcher’s location: the closer you are to a business’s address, the more likely you are to see it among local results. Possum also resulted in greater variety among results ranking for very similar queries, like “dentist denver” and “dentist denver co.” Interestingly, Possum also gave a boost to businesses located outside the physical city area.
8. Fred
Launch date: March 8, 2017
Hazards: Thin, affiliate-heavy or ad-centered content

How it works: The latest of Google’s confirmed updates, Fred targets websites that violate Google’s webmaster guidelines. The majority of affected sites are blogs with low-quality posts that appear to be created mostly for the purpose of generating ad revenue.