Wednesday, June 20, 2018

SEO 101: Defining "Algorithm"

What is an algorithm?

Most SEO content presumes prior knowledge of the nature of algorithms as well as specific knowledge of search engine algorithms. At The Organic SEO Blog we try to define most SEO-specific words in each post. However, the word algorithm is so ubiquitous we usually presume, like other SEO publications, prior knowledge.

Perhaps we shouldn't. Over the years we've received more than a few reader emails (mostly from owners of small online shops) asking, "What is an algorithm?" or "What is the algorithm?"

These two questions, however similar, speak to two different points.

Algorithms are often simple and profound [Photo Source]

What is an Algorithm?

Many people have a sense of algorithms, in general, though many feel the same way as Jacob Brogan, who admitted on Slate: "Can I level with you? I’m not always sure I know what people are talking about when they say algorithm?"

Despite his confessed ignorance, we like Brogan's definition of the word algorithm: "A set of guidelines that describe how to perform a task."

Read: "What’s the Deal With Algorithms?"

Simple, right?

Perhaps in application but certainly not in consequence. In one sense, algorithms rule our world--at least our online word--and very often algorithms contain implicit biases. As we've noted before:

"We end to think about algorithms as neutral, but really, although engineers base algorithms on mathematical principles, most of the judgements about those principles are exactly that--judgements, made by biased humans."

Read: "On Algorithm Bias"

For example, algorithm bias influences your Facebook feed and so much more. Yet algorithms are inescapable--and many benefit our lives profoundly. As a TopCoder article notes:

"Almost everything that you do with a computer relies in some way on an algorithm that someone has worked very hard to figure out. Even the simplest application on a modern computer would not be possible without algorithms being utilized behind the scenes to manage memory and load data from the hard drive."

Of all these algorithms, though, one specific algorithm tends to get a lot of attention--and especially  in the SEO world.

What is the Algorithm?

In SEO circles, the algorithm is Google's algorithm--the single set of guidelines that makes the search community go round.

Google often "refreshes" its algorithms monthly, but "updates" are less frequent, and usually more consequential. Whatever the case, talk of Google's algorithm is a daily affair. And for all that, it is often misunderstood.

A few years ago Google's John Mueller wrote this simple comment in a help thread:

"In practice, a site is never in a void alone with just a single algorithm. We use over 200 factors in crawling, indexing, and ranking."
If you're an SEO layperson, pay attention to this comment. It's simple, yet profound, and it gets to the heart of what Google's "algorithm" is all about.

In fact, this quote offers a good working definition of Google's algorithm: a system for crawling, indexing, and ranking websites.

Viewing these three functions--crawling, indexing, and ranking--separately also offers a helpful view of exactly why algorithms--and SEO firms--exist.


Web "crawlers"  are often called "spiders," and this is the easiest way to envision their function. Spiders crawl the Internet in an attempt to gather valuable information from websites. If a certain website links to another page on the same site, or a to a different site, the spider will follow the link and gather more information.

In this way, the spider creates a web of information that is sent back to Google for indexing.

It's important to note: not every website is crawled. This is why it is important to follow today's web development standards, and why, we believe, it is important that your website developer understands the basics of SEO.

Read: "Website Development: The Perfect Job for Spock." 

Beyond making sure your website is crawled, a website developer with knowledge of SEO may or may not make "granular choices" to further refine how it is crawled. Again, your website developer should know about these choices. As Google writes here:

"Most websites don’t need to set up restrictions for crawling, indexing or serving, so their pages are eligible to appear in search results without having to do any extra work. That said, site owners have many choices about how Google crawls and indexes their sites through Webmaster Tools and a file called “robots.txt”. With the robots.txt file, site owners can choose not to be crawled by Googlebot, or they can provide more specific instructions about how to process pages on their sites."


The information obtained from crawlers needs to be organized. This is the function of indexing. This process is self-evident: Once Google receives information from the crawler, it creates an index, much like the back of a non-fiction book, so that it can easily retrieve the information for future use.

As Google says:

"The web is like an ever-growing public library with billions of books and no central filing system. Google essentially gathers the pages during the crawl process and then creates an index, so we know exactly how to look things up. Much like the index in the back of a book, the Google index includes information about words and their locations. When you search, at the most basic level, our algorithms look up your search terms in the index to find the appropriate pages."

SEO can have a profound influence on how a website is discovered by the crawlers, but indexing is purely a a Google function.


Ranking is the end-result of crawling and indexing. Once the information is gathered, and sorted, it is then ranked in a way that Google believe is most beneficial to the browser's experiences.

Attentiveness to crawling and indexing is an important function of SEO, but attentiveness to the many ranking singles is really what sets the best SEO specialists apart.

Backlink has a very helpful list of the "complete list" of Google ranking factors. Some of this list is speculative (Google is often stingy about offering ranking single information), but much of it is really spot-on. Some factors are more important than others; and some matter very little, although it's good to be attentive to each and every one.

Also, you might read our post on Google's confirmed top three ranking signals: "Links, Content, and RankBrain."


If you're looking for more information on algorithms, try Google itself.

Here on The Organic SEO Blog we discuss algorithms not only as functions but ideas. If you're looking for a more philosophical view of algorithms, please read: "A Frank Look at Algorithms."

For a more topical view of algorithms, try: "Algorithms Have Consequences."

Making SEO Simple for Local Businesses: Stepman's SEO

If you'd like to speak directly to an SEO specialist who understands the complexity of algorithms, we suggest calling our sponsor, Alex Stepman, of Stepman's SEO: 215-900-9398.

Stepman's SEO offers a full range of online marketing services to help you work with the search engine algorithms--not just Google, but every algorithm.