What is an algorithm and what is it for? How does Google’s algorithm work?.

If you work in the digital marketing sector, you’ve probably heard the word algorithm. That’s why today we want to explore what an algorithm is, what it's used for, and how understanding it can help improve results. Keep in mind that algorithms are constantly changing, improving, and being updated — so staying informed is essential to executing a successful strategy.

What is an algorithm?

In mathematics, logic, computer science, and related fields, an algorithm is a set of defined and unambiguous instructions or rules, organized and finite, used to solve a problem, perform a computation, process data, or carry out other tasks or activities.

As mentioned earlier, this concept also applies to algorithms used in various online marketing processes, such as search engines and social media. These systems use rules to give more or less visibility to content, which in turn affects rankings, reach, and ultimately, conversions.

How does a computer algorithm work?

Computer algorithms operate through an input-output system. They take the input and apply each step of the algorithm to that information until a solution is found.

A great example of this is search engines. They function as algorithms that take a search query as input and comb through their database to find relevant results that match the query terms. The system then outputs those results.

What is an algorithm used for?

Algorithms can be visualized as flowcharts, where each shape represents a specific type of instruction. In simple terms, their function is to create a structured plan before coding begins.

They are not tied to any specific programming language, as they can be represented in many different ones. Essentially, algorithms are the foundation of any program. A program is a set of algorithms encoded in a programming language to be executed on a computer.

What is Google's algorithm and how does it work?

As mentioned earlier, Google’s search algorithm is a complex system that allows Google to search, rank, and deliver the most relevant pages for a given search query.

The ranking system consists of multiple algorithms that consider several factors such as quality, relevance, and page usability.

How does Google’s search algorithm work?

Many factors come into play. Let’s focus on the 5 main ones (officially listed by Google) that influence the results returned for a specific query:

1. Understanding the query

To deliver relevant results, Google must understand exactly what the user is looking for and what their search intent is. This involves:

1. Meaning of the words: What exactly do the words mean in natural language?
2. Search intent: Is the user looking for a definition, a review, to make a purchase, or to find a specific website?
3. Content freshness: Is the query time-sensitive and requires up-to-date information?

Sometimes it's straightforward. A search like “buy new iPhone” clearly indicates intent, meaning, and freshness. But with broader queries, it’s harder to determine intent. In these cases, Google shows what it believes are the best results and offers additional options to refine the search.

2. Relevance of pages

Next, the search engine needs to find pages that are relevant to the query — those that best answer the user's question.

It does this by regularly crawling and indexing websites and analyzing their content. Keywords play a key role. If the search terms or related phrases appear on a page, it’s likely that the page is relevant.

3. Content quality

Since millions of pages may match a query, Google prioritizes those with high-quality content that demonstrate:

1. Expertise
2. Authoritativeness
3. Trustworthiness

A key element here is the PageRank algorithm, which considers both the quality and quantity of links pointing to a page.

Google’s PageRank

PageRank is a numerical value assigned to each page to help prioritize search results. It’s based on the assumption that more important pages are likely to receive more backlinks from authoritative websites.

Three main factors affect a page’s PageRank:

1. Number of backlinks
2. Quality (PageRank) of the linking page
3. Number of links on the linking page

In short: the more high-quality backlinks a page receives, the more likely it is to be considered high quality by Google.

Additionally, Google uses spam-detecting algorithms to filter out low-quality pages using black hat SEO techniques.

4. Usability of pages

Once Google has evaluated relevance and quality, it assesses usability and user experience.

This includes technical factors like:

1. Mobile responsiveness
2. Proper display across browsers
3. Page speed
4. Site security

These may not be the most important factors, but they are considered when other aspects are equal.

Note: Google increasingly incorporates Page Experience signals into its ranking systems. For example, Core Web Vitals — metrics related to speed, responsiveness, and visual stability — became part of the algorithm in 2021.

5. Context and settings

Last but not least, search results are heavily influenced by the user’s context and preferences, including:

1. User location
2. Search history
3. Search settings

Google’s search quality evaluators

In addition to algorithms and machine learning systems, Google gathers feedback from real human evaluators.

Google hires thousands of third-party workers (search quality raters) to assess the quality of search results and ranked pages.

Here’s how Google explains the use of this data:

These ratings do not directly affect a page’s ranking. No one decides that a particular source is ‘authoritative’ or ‘trustworthy’... Instead, the ratings are a data point that, when aggregated, help us measure how well our systems are working to deliver great content.”

So, these ratings don’t directly affect rankings, but the data collected is used to improve the algorithm.

Google algorithm updates

Google’s algorithm updates fall into two categories:

1. Minor updates
2. Core updates

Google modifies its algorithm very frequently — several times a day. Most of these changes are small and go unnoticed.

In addition to these, Google rolls out a few core algorithm updates each year. These tend to spark discussion in the SEO community and often get nicknames.

Major Google core algorithm updates

Some of the most significant Google updates that have shaped the current algorithm include:

• Panda (2011): Targets low-quality pages, keyword stuffing, and duplicate content. Became part of the core algorithm in 2016.
• Penguin (2012): Focused on manipulative link practices — low-quality, spammy, or overly optimized backlinks.
• Hummingbird (2013): Enhanced Google’s understanding of search queries, shifting from exact-match keywords to broader topic interpretation.
• Pigeon (2014): Improved the quality and accuracy of local search results.
• Mobile Update (2015), aka Mobilegeddon: Prioritized mobile-friendly pages in mobile search results.
• RankBrain (2015): A machine learning component of the Hummingbird algorithm that helps deliver more relevant results.
• Fred (2017): An unconfirmed update targeting low-quality, ad-focused content that violated Google’s quality guidelines.
• Medic (2018): A broad core update that significantly impacted YMYL (Your Money or Your Life) content, especially health-related sites.
• BERT (2019): A natural language processing algorithm that better understands the context of search queries using the BERT model.

Since 2020, Google has started pre-announcing the names of major updates to avoid confusion within the SEO community.

What to do if you’ve been affected by a Google algorithm update

1. Be patient: Core updates often roll out over several days. Don’t rush into “quick fixes” that may do more harm than good.
2. Trust reliable sources: Don’t believe every “SEO expert” in forums claiming to have a “100% verified” solution. Wait for in-depth analyses from trusted sources like Search Engine Journal or Moz.
3. Make sure action is needed: Sometimes, the best response is to wait. Many updates are slightly refined or even rolled back after a few weeks. Don’t fix what isn’t broken.
4. Improve: If you identify real issues that may have caused a drop in rankings, take the opportunity to fix them. Or even better, rethink your entire SEO strategy — focus on quality over quantity.