Lesson 1 : Crawling, Indexing, and Ranking
The Basics of How Search Engines Work
Let’s discuss about how search engines really work. Even though Google’s algorithm is very complicated, at its core, it is just a program that looks for patterns. Google will give you a list of websites that match the pattern of what you’re looking for when you search for a keyword phrase.
Most people don’t know that when they do a search on Google, they are not actually searching the live web. In fact, they are looking through Google’s index of the web. Google’s saved copies of the sites it has crawled.
How Google Discovers Content on the Internet via Crawling
Google crawls the web with little programs called “spiders.” The spiders are the actual way that Google finds content. Basically, a spider will start on a page and look at all the information on that page. It will navigate through the links on that page and look at the content on those pages. Then it follows the links on those pages to find more content, and the links on those webpage result to even more content… The spiders keep crawling at a huge rate until they have crawled the entire internet.
Indexing is the Method Google Uses to Store Crawled Content
Google keeps a copy of all of these pages as they are crawled by its spiders. Google’s index is organized in a way that facilitates fast searching across its many billions of indexed pages. Google uses its index to return results that are relevant to your query when you conduct a search.
Here is where SEOs come in; they attempt to have an impact on the rankings. Once Google has retrieved a list of pages from its index, it uses an algorithm to evaluate the list and assign a relevance score to each page.
Page Prioritization in Google's Indexing Algorithm
(AKA "Ranking")
A search for “How to plant Peonies” would cause Google to scour its index for results, displaying a list of every website that discusses the subject. The algorithm will then be used to sort the results in order of importance so that only the most relevant websites are shown.
Hundreds of ranking factors exist, each with its own value. The algorithm will look at several hundred things, like the page content, the number of external links, and the quality of the site, to figure out how relevant something is.
Ultimately, the goal of search engine optimization is to move the needle on relevance scores. If we optimize the right signals, Google’s algorithm will determine that the page is more relevant—that it is a better answer to the question being asked—and it will rank it higher in the index. If you typed “Denver omelette recipe” into Google, it would return a list of all the websites it could find that featured such a recipe. The algorithm will then be used to sort the results in order of importance so that only the most relevant websites are shown.
I’m hopeful that you were able to take away something useful from this introductory SEO course and apply it to your virtual assistant work. If you have any questions, please leave a comment and I will answer them as soon as I can. The next tutorial will be ready in two days.
