How Does a Search Engine Actually Work?

In Digital Marketing, SEO, Technology by Mo IqbalLeave a Comment

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These days, pretty much everyone has heard of SEO, and most small business owners have started or at least considered some kind of SEO campaign. And while most people are generally aware of what SEO does, not many people really understand how search engines work, and how one can truly optimize a website for search.

This is one of the fundamental building blocks of a digital marketing education. If you’re going to begin an SEO campaign, it is vital to understand the landscape in which the campaign will operate. And while Google is a massively complex company with some of the most intricate software in the world, developing a high-level understanding of how a search engine works doesn’t require a PHD in computer science. In this post, we’ll sketch the basics of how a search engine works and how this functionality interacts with SEO.

Step 1: Crawling the web.

google-botThe first thing that a search engine must do is crawl the web. Basically, a search engine’s core software is something called a robot, spider, or crawler, which basically downloads web content. The crawler jumps from page to page, following links, and downloading all the content that it can process. Modern web-scale search engines like Google and Bing will basically attempt to download the entire internet. It’s important to also understand that while Google will crawl things like images, videos, and flash content, today’s search engines can only really “understand” text content. Additionally, Google can’t crawl everything: if a website is poorly configured or just contains too many pages, Google won’t be able to crawl the whole website. A key inital part of SEO is ensuring that a website is configured properly to easily be crawled by Google.

Step 2: Indexing content.

database-systemAfter Google has crawled a page, that page is then said to be “indexed”. This means that it has been included in Google’s massivedatabase of online content, and is now findable in search. The key point to understand is that when you search Google, you are not searching the live internet: you’re searching Google’s downloaded copy of the internet. The Google index is a massive saved repository of every bit of web content that Google has ever crawled, and every Google search pulls results from the Google index. If you’re a webmaster or business owner, it’s easy to see exactly what content from your website has been indexed by Google. Just go to Google search and type in “”. The results will show you everything that Google sees on your domain. If you notice that content is missing, you may have some technical problem in how your site is built that is preventing proper Google indexation.

Step 3: Ranking content.

BauklötzeWe’ve already discussed doing a search on Google will pull results from the Google index. But how does Google actually decide which pages should appear in the first few results? Google has billions of pages indexed, and the average search term will likely generate millions of relevant pages. But only a very small fraction of these pages will usually generate traffic from Google. To decide which pages to rank, Google generally looks at two primary categories: page relevance, and page authority. These are the two main aspects of a website that SEOs attempt to influence. Relevance basically refers to keyword targeting. A webpage that has the term “digital cameras” in the title, heading, and body is much more relevant for that term than a page that just has those words once in the copy. SEOs improve relevance by applying specific keyword targeting optimizations to a website in key areas that Google considers important. Authority basically means how many links (and possibly social mentions) a website has. The more times a website is linked to, the more authoritative Google considers it to be, and the higher it will rank. SEOs work on improving authority through the practice of link building.

These 3 steps represent a high-level review of the actual operations of a search engine. If you understand these core processes, you’ll be in a much better position to direct a successful SEO campaign.

It’s also important to remember Google’s incentives and business model. Google rewards relevant and authoritative websites primarily because it assumes these websites will satisfy users, who then will hopefully come back and use Google again. Of course, during that process, Google hopes these users will clicks some AdWords ads, which is how Google makes money from the whole operation described above.

It’s also valuable to consider that of course, the overall SEO and search engine process is much more complex than what’s described above. Google’s algorithms are some of the most advanced technology on the web, and are incorporating increasingly sophisticated technologies to better crawl and rank web content. If you’re interested in learning more about SEO and applying search engine best practices to your business, the team at Tech-Critic would love to help. Contact us today for a free SEO consultation.

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