Google Algorithm and Other Core SEO Concepts Explained

Did you know that Google keeps updating its algorithm almost every day? While you may not notice most of the small changes, some major updates affect your: 

• SEO strategy
• Search rankings
• Web traffic 

So, you need to know these updates to maintain or improve your rankings on the Search Engine Result Pages (SERPs) and avoid Google penalties. 

First things first!

What is an Algorithm?

It’s an automated process or formula that search engines use to retrieve stored information and show the best results for a query, keyword, or phrase. The order of these results is based on different ranking factors and signals.

Google Algorithm

A complex algorithm that Google uses to determine which webpages show up on the SERPs for a search query and where they appear in the rankings. As mentioned, Google keeps updating its algorithm, so it’s important to know these changes to keep your site SEO-friendly.

Algorithm Change

Some changes go unnoticed, while major changes usually have a bigger impact.

Search engines make three types of algorithmic changes:

• Algorithm update, which involves changing certain signals of the existing algorithm
• Algorithm refresh, which means rerunning the existing algorithm while using the same signals
• New algorithm, which means adding a completely new algorithm to return better results more quickly 

Since the last decade, Google has rolled out several major updates. Let’s discuss each one of them in order of their release date.

Google Panda Algorithm (February 2011)

Panda aimed at filtering sites with “shallow” or “low-quality” content, such as those produced by content farms. Initially known as “Farmer,” the update added new signals to help Google reduce the visibility of lower-quality sites in the search results. 

The algorithm update assigns a quality score to webpages, which is a major ranking factor. With subsequent updates in the following years, Panda also identifies plagiarized or duplicate content, keyword stuffing, or user-generated spam.

Google made Panda part of their core ranking algorithm in January 2016, and since then, the updates have become more frequent. So, penalties and recoveries happen faster in Panda. 

Google Penguin Algorithm (April 2012)

Google’s next major update, “Penguin,” targeted websites with spammy, unnatural, or irrelevant links. The goal was to downgrade sites that adopted low-effort link-building practices, such as buying links from link farms.

Penguin reduced the visibility of sites involved in violating quality guidelines, including keyword stuffing or manipulative link schemes, to boost search rankings. Following a series of updates, Google permanently incorporated Penguin into their core algorithm in 2016, which means the refreshes happen in real-time.

Google Hummingbird (August 2013)

In 2013, Google released another algorithm, “Hummingbird,” to interpret and understand natural language search queries. The aim was to provide relevant results that satisfy the search intent instead of showing results based on certain keywords. 

Natural language processing depends on three things: synonyms, co-occurring terms, and Latent Semantic Indexing (LSI). So, you can make your page rank for a query even if it misses the exact words but answers the searcher’s question. 

Mobile (April 2015)

As the name implies, this update emphasized the mobile version of a site. The aim was to ensure webpages offered cross-platform usability. The subsequent updates in 2018 and 2020 also focused on page speed and mobile usability or mobile-friendliness (an important ranking factor).

RankBrain (October 2015)

RankBrain, one of the top three ranking factors, analyzes patterns in search queries. It then sorts through billions of pages to provide the most relevant answers. Google tested this machine learning system on a large fraction of search results before rolling it out in October 2015 and later using it on all searches.

Before RankBrain, Google used to show results matching the exact words in the query. With this AI-powered algorithm, Google now connects words to concepts to understand the search intent. It helps Google to go beyond a user’s query and consider other factors as well, including synonyms, implied words, and even the user’s search history.

Medic (May 2018)

Medic was a part of the August 2018 broad core algorithm update that affected Your Money Your Life (YMYL) websites, which lacked authority. These websites have content that can directly impact a reader’s life-altering decisions, such as those related to health, finance, or law.

The update implemented some of the E-A-T (Expertise, Authority, Trust) signals to evaluate the content of these sites. As a result, many top websites experienced a significant drop in their rankings, while the under-rewarded sites made huge improvements. You can improve your rankings by producing quality content.

BERT (October 2019)

Bidirectional Encoder Representations from Transformers (BERT) was released in October 2019. Using natural language processing, the update helps Google understand queries and the content on web pages to provide relevant search results. 

BERT allows the search engine to interpret text and identify poorly written content that lacks focus or context. It rewards sites with good, meaningful writing, so it’s important to avoid fluff or thin content.

Core Updates (2017 – Present)

Google refers to the major updates to its algorithm as core updates since 2017. These updates are non-specific, which means that there is less information about 

• What these updates are
• What parts of the search do they improve?

SEO specialists track rankings after a major core update to determine what has changed. However, there are no conclusive observations. 

The latest major core update came out in March this year; it’s a more complex algorithm update than the previous ones. Here is what we know so far: 

• It includes several updates and releases, which means more fluctuations in rankings.
• Google’s helpful content system is now a part of its core ranking system.
• The new update will help Google reduce unhelpful, low-quality, and unoriginal content in search results by 40%.

Here are a few other terms related to the Google algorithm that you should know.

Google Penalty

Google takes manual action against sites that violate its quality guidelines, such as using questionable links, keyword stuffing, or other black-hat SEO tactics. 

A human reviewer manually reviews your website and confirms that a certain page or the entire website does not comply with the rules or a recent change in the algorithm. You can face two types of consequences for the violation, whether it’s intentional or not:

• Demotion in the search rankings
• Removal of the entire website from the SERPs

Mobile-First Indexing

Since 2018, Google has started using the mobile version of your website to crawl, index, and rank it. The shift from the desktop version to mobile means Google favors sites that are mobile-friendly, load faster, and provide a seamless user experience.

Latent Semantic Analysis (LSA)

It’s a method in natural language processing that helps Google understand the context of a word by connecting words to concepts. It focuses on synonyms and implied words that searchers may use when looking for a product or service.

Google Search Quality Rater Guidelines (QRG)

QRG is a document with a collection of metrics that Google’s internal quality raters use to evaluate content quality. The document includes a list of ranking signals and guidelines that Google wants to add to its algorithm.

It also features the concepts of E-A-T (expertise, authority, trust) and E-E-A-T (experience, expertise, authoritativeness, trustworthiness).

The quality raters evaluate the search results based on these guidelines to ensure compliance. Google kept the document confidential initially but later released it online. 

Search Engine Results Page(s) or SERPs

It’s the page of results that you see on your screen in response to your search query. The first page usually displays the top 10 best and most relevant websites that satisfy the search intent. In addition to the web pages, Google may also display other features based on your query, such as

• Images
• Videos
• Featured snippet
• AdWords Ads
• Tweets 
• People Also Ask
• Related search queries

Want to learn more about other important core concepts and SEO terms? Check our Knowledge Center.