Understanding the ‘Plumbing’ of SEO – How it Works

Understanding the ‘Plumbing’ of SEO – How it Works

There are a lot of things in the world that we don’t fully understand, but that need to work so that our lives can go on. Things like Wi-Fi and the reliable supply of water and electricity are just a few examples of goods and services that only a small percentage of people fully understand, but that we all rely on.

The same concept applies to SEO: only a few people fully understand it, but millions of businesses rely on good search engine optimisation to get better ranking on results pages. That better ranking can drive new browsers, that then turn into paying customers. And from there, revenue and profit can flow.

To help break down the walls, we’ve come up with a ‘SEO Basics’ post so that you can better understand the concepts that make SEO work.

Web Crawling

The first thing that all search engines must do is ‘crawl’ the internet, and all the websites and pages in it.

This is sort of like an explorer from the 1600’s setting out on a ship to map parts of the world that had not been explored yet. But instead of using ships on the ocean, search engines send out web crawlers to find content. Content that these crawlers find can range from entire web pages to single images. It can also include uploads to web pages such as documents and videos.


Indexing is probably the simplest aspect of SEO to understand. The ‘explorers’ that search engines send out (the crawlers) gather absolutely vast amounts of information. Imagine this information as though each piece of content (pages, images, videos) was represented by a single sheet of A4 paper.

If all of this paper was thrown all over the floor, perched on tables and stacked on shelves it would be borderline impossible to find anything useful in it. Even worse, relevant information would probably never be found when you went to look for it.

What is needed is a ‘system’ to sort all of those pages into logical categories and then store them. This is exactly what libraries do with books. They are grouped by fiction or non-fiction, and then by genre, and then further by author.

Google search indexing borrows from these same principles to sort and catalogue digital data. It also ‘cleans’ a lot of the data that the crawlers find. If there are duplicates, low quality content or very old content, then this is generally filtered out of the results.

Search Engine Ranking

The ranking part of the process is a direct result of the two steps that you’ve just read. When someone searches for something, the search engine looks through its index for the most relevant content. Then, based on the past behaviour of searchers, it ranks all of the relevant content into what it thinks is most likely to answer the question the searcher is asking.

And as a final note, industry estimates put the total number of searches performed as 90% attributable to Google, so while other search engines exist, it is the best use of your time to optimise for Google searches before even thinking about any other service.