How Google finds and ranks pages

SEO (search engine optimisation) means helping a website appear in search results for the things its customers search for, without paying for ads. Most of this course focuses on Google, because it is the largest search engine in most countries, but the same ideas help on other search engines too.

Three stages: crawl, index, rank

1. Crawling. Google uses automated programs (often called crawlers or Googlebot) to discover pages. They find new pages mainly by following links from pages they already know, and from sitemaps that site owners submit.

2. Indexing. Google tries to understand each page: its text, images, videos, title and structure. Useful pages are stored in Google's index, a huge database. A page that is not in the index cannot appear in results.

3. Ranking (serving). When someone searches, Google looks through its index and shows the results it judges most relevant and useful for that search. Many signals are involved, such as the meaning of the search, how well the page answers it, the quality of the content, how usable the page is, and the searcher's language and location.

What this means for SEO

• If Google cannot find a page, nothing else matters (crawling).
• If Google cannot understand or does not store a page, it cannot rank (indexing).
• If the page is not the most helpful answer, it will rank below better pages (ranking).

Good SEO work checks all three.

Organic results and ads

The results page often shows ads (marked "Sponsored") and organic results. Ads appear because someone pays per click. Organic results cannot be bought. SEO is about organic results; paid search ads are a separate skill (covered in our Digital Marketing course).

A quick check you can do now

Type site:example.com into Google (replace with any website). It shows pages Google has indexed from that site. It is a rough check, not an exact count, but it quickly shows whether a site is being found at all.

Google Search Console

Google Search Console is a free tool from Google for site owners. It shows which searches bring visitors, which pages are indexed, and problems Google found. Almost every SEO job uses it, and you will learn it throughout this course.

Practice task (10 min)

1. Search site: followed by the address of a website you know (for example a local shop's site).
2. Note roughly how many pages appear and whether the important pages are there.
3. Search one product or service that business offers. Is the site in the organic results, the ads, or not visible?