How Search Engines Work?

How Search Engines Work?

In order to grasp the concept of search engine optimization (SEO), it is beneficial to familiarize yourself with the functioning of search engines. The primary purpose of search engines is to assist users in locating specific online information. To accomplish this, they assess the vast array of websites and web content that constitute the World Wide Web, determining which sites are most relevant to a given query.

The internet itself is a network of interconnected pages and digital resources that users access worldwide. Naturally, you can directly access these documents by entering a web page's URL or web address in a web browser. However, more frequently, individuals reach websites through the use of a search engine, which presents a significant advantage for business owners.

What makes the web work?

Web pages are essentially structured documents utilizing HTML, a web programming language designed for the inclusion of hyperlinks that establish connections between different pages. This is the fundamental concept to grasp when it comes to comprehending how the internet operates.

The content within web pages encompasses various elements, including text, images, forms, videos, hyperlinks, and more. Users typically visit web pages with the primary purpose of accessing and engaging with this content. Whether it's reading, viewing, listening, or performing tasks like making a purchase or subscribing to a newsletter, the content is what draws them. The navigation across web pages is facilitated through the utilization of links.

These activities are made feasible due to the content that is encoded into each web page. The inherent nature of the web fosters seamless transitions between pages, enabling users to move from one to the next according to their specific intentions.

What is a website?

A website comprises a group of web pages hosted under a common domain and usually under the administration of a single entity. As an illustration, you can access the KYourC homepage at the web address

In this web address, "" represents the domain. When you examine other URLs within this site, you'll observe that they also use the same domain, despite variations in the complete URL. 

For example:

KYourC also uses links to direct visitors to other areas of the website. For example, from the navigation area at the top of each page, you can easily click through to another page on the site. That’s possible through internal links, which are links between pages on the same domain.

External links are references to web pages from different domains, as exemplified by the author's byline at the end of this article. On each page, kyourc incorporates a footer section, which aids users in navigating to specific pages through a combination of internal and external links. In this context, the external links direct users to social media profile pages.

Typically, websites employ more internal links than external ones. Generally, all the pages within a website link to other pages within the same site, creating an interconnected network of documents.

Internal links establish connections between pages that share a relationship and exist within the same domain. However, the real power of the internet lies in external links. External links establish connections to web pages that exist beyond the confines of a single organization, contributing to the vast network of billions of web pages.

The motivations for using external links can vary. For instance, you might include a statistic in an article and wish to link to the data source on another website. This not only enhances the credibility of your content but also contributes to the expansive and interconnected web.

What a search engine does

Search engines perform 3 main tasks:

  1. Crawling
  2. Indexing
  3. Delivering search results

In simple terms, crawling is the act of accessing web pages on the internet. Indexing is deriving meaning from the content of web pages and building a relational database between them. Delivering search results means interpreting a user’s search query, then delivering results from the index that best answer this query.

How crawling works

Web crawling, performed by a computer program known as a crawler or spider, involves the task of visiting web pages and extracting their HTML content. The key objective of a crawler is to identify links.

Every web page is uniquely identified by its URL, which can be entered into a browser's address bar to access the page. These web pages are essentially constructed with content that is structured using HTML.

HTML is a language that machines can interpret, enabling an external program like a crawler to visit a URL, extract its HTML content, and access the information in an organized manner. It possesses the capability to distinguish between text and hyperlinks.

When crawlers analyze the HTML code of a page, such as the one containing the article you're currently reading, they identify each paragraph by the presence of a code element called the paragraph element or p-tag at the beginning and end. This p-tag serves as a marker for a block of paragraph text; the p-tag at the start opens the paragraph element, and the one at the end closes it. While this code is hidden from regular users, crawlers can detect and understand that the page contains text intended for human readers.

Links are also detectable and interpretable by crawlers due to their HTML code. Programmers define links using an anchor element at the beginning and end. These links also incorporate an "attribute" indicating the hyperlink's destination and the "anchor text," which is the visible linked text, typically displayed in browsers in blue with an underline.

For a crawler, the process of parsing this HTML to distinguish text from links is relatively straightforward. However, a single web page comprises more than just paragraphs and links. To explore this data yourself, you can visit a web page in your browser, right-click anywhere on the screen, and select "View Source" or "View Page Source." On most pages, you'll discover hundreds of lines of code.

For every web page a crawler encounters, it dissects the HTML, breaking it down into its constituent elements for further processing. The crawler extracts all the links found on the page and schedules them for crawling. Essentially, it establishes a feedback loop:

  1. Crawl URL
  2. Find links to URLs
  3. Schedule URLs for crawling
  4. Crawl URL

You can give a crawler a starting URL, and it will continue crawling until it exhausts all new URLs to explore, which could amount to thousands or even millions of URLs.

In summary, crawling is a method of discovery, where search engines employ web crawlers to locate web pages by following links as guideposts to their next destinations. This underscores the significance of internal links within your website, as they aid search engine crawlers in discovering all the pages on your site. Through external links, these crawlers navigate the network of interconnected pages that constitutes the internet.

How indexing works

As search engines traverse the internet, they compile a repository of discovered web pages, a resource they subsequently employ to construct their index.

Imagine the index found at the back of a textbook from your school days. If you wished to explore the topic of cellular structure, you would refer to the index of a biology book to locate the relevant pages. The process of indexing web pages operates in a similar manner.

An index proves invaluable because it facilitates rapid searches. Search engines like Google require a swift method to retrieve information and provide search results, underscoring the importance of indexing.

Search engines meticulously process each web page they crawl, parsing the HTML document to isolate all the links. This enables them to retain the destination URL for every link, along with the associated anchor text. Simultaneously, they extract and organize the textual content, breaking it down into individual word occurrences.

Leveraging this parsed data, search engines construct an inverted index, linking each web page URL with the words contained on that page. Once a URL is stored in this manner, it becomes part of the index, thereby having the potential to appear in search results.

For each indexed URL, search engines retain as many of these word-URL connections as they consider relevant, in addition to other relevant metadata they've gathered about the page. This dataset is what they rely on when determining which URLs will feature in their search results.

How search results get delivered

Crawling and indexing are automated and continuous processes. The index is constantly updated in real-time, with data collection and storage happening in the background, unaffected by user search queries.

However, the delivery of search results relies entirely on user input through their search queries. When someone searches for something like "best television streaming service," the search engine matches each word with documents in its index.

But simply matching words with indexed pages results in a vast number of documents, so the challenge lies in determining how to display the most relevant matches first. This is where it becomes complex, and it underscores the importance of SEO. How do search engines decide which results to show from billions of possibilities? They use a ranking algorithm.

Algorithms are essentially sets of rules that computer programs follow to execute specific processes. A ranking algorithm is a combination of numerous algorithms and processes working together.

The ranking algorithm takes into account various factors, including:

  1. Whether all the words in the search query appear on the page.
  2. The presence of specific combinations of words on the page (e.g., "best" and "streaming").
  3. Whether the words are in the title of the page.
  4. Whether the words are present in the URL of the page.

These are just basic examples, and there are numerous other factors that the ranking algorithm considers when determining which results to display. These factors are known as ranking factors.

Google's dominance as a global search engine is attributed to one simple reason: its ranking algorithm outperformed those of its competitors.

Making sense out of complexity

Search engines operate as highly intricate systems, handling vast volumes of data on a daily basis. They employ intricate algorithms to interpret this information and meet the needs of search users.

Countless elite software engineers worldwide are continuously enhancing and fine-tuning these systems. This responsibility places companies like Google at the forefront of some of the most advanced technology developments globally.

Cutting-edge technologies such as machine learning, artificial intelligence, and natural language processing will increasingly influence how search results are delivered. You don't necessarily have to grasp all the intricacies, but through the application of fundamental best practices, you can enhance the discoverability of your website for the specific words and phrases that your customers are searching for.

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