What is SEO? Search engine optimisation explained in plain English

Short answer: SEO stands for search engine optimisation. It is the work of making a website easy for search engines such as Google to find, understand and show to people searching for what you offer. The goal is more visitors from the ordinary search results, without paying per click.

What does SEO mean?

When you search on Google, you get two kinds of results: ads, labelled as sponsored, and organic results. SEO is about the organic ones. You cannot buy a place there. Google says it never accepts payment to include or rank a site, and that advertising does not affect how you appear organically (Google Search Central).

Google's own guide describes SEO as helping search engines understand your content, and helping users find your site and decide whether to visit it (SEO Starter Guide). So SEO is not a trick, but a way to make a good page easy to find.

You may also have heard of SEM, search engine marketing, which usually means paid visibility such as Google Ads. SEO and ads work best together: ads bring traffic straight away, while SEO builds something that keeps bringing traffic without a cost per click. Read more about advertising.

How Google chooses which pages to show

Google describes the process in three stages (Google Search Central):

1. Crawling. Google's robots follow links and find new and updated pages.
2. Indexing. Google tries to understand what each page is about and stores it in its index.
3. Serving results. When someone searches, Google picks the pages in the index that best answer the query.

If a page cannot be crawled or indexed, nothing else matters, so good SEO always starts with the basics. Read Google indexing for how to check. Google handles about 91 percent of searches in the UK (StatCounter), so it is Google most UK businesses should optimise for.

The three parts of SEO

1. Technical SEO

Technical SEO is about the website working for both robots and people:

• pages can be crawled and indexed, with a sitemap and no accidental blocks
• the site is fast and works well on mobile
• every page has a clear title, a description and a logical URL
• the same content does not sit on several URLs

Google measures user experience partly through Core Web Vitals, which cover loading, responsiveness and visual stability (web.dev). Read more about technical SEO.

2. Content

Content is what actually answers the search. The key idea is search intent: what does the searcher really want? Someone searching "what is seo" wants an explanation. Someone searching "seo agency Manchester" wants someone to hire. The same page rarely serves both well.

Google recommends content written for people, not search engines, that shows real knowledge and experience (Google Search Central). A good rule of thumb is one page per topic, with one clear main keyword.

3. Authority and links

Links from other websites work like recommendations. A link from a relevant, trustworthy site says your content is worth showing. There is no shortcut: bought links and link schemes break Google's rules and can have the opposite effect (Google's spam policies).

Local SEO

If you sell to customers in a particular town or region, local SEO is often the fastest route to visibility. It is about appearing when someone searches for "electrician Leeds" or "accountant near me", both in the map and in the ordinary results.

The foundation is a complete, up-to-date Google Business Profile, the same name, address and phone number everywhere online, reviews from real customers, and pages on your site that clearly say where you operate. Read more about local SEO and Google reviews for business.

Why SEO matters for businesses

• You are visible when the need exists. The searcher already has a problem to solve.
• The clicks cost nothing. You pay for the work, not per visitor. A page that ranks can bring traffic for years.
• It builds trust. Many people skip the ads and trust the organic results more.
• It works with everything else. A fast, clear website converts better wherever the visitor comes from.

The downside is time. SEO is rarely quick, and nobody can promise first place. Google itself says no one can guarantee a number one ranking (Google Search Central). Read How long does SEO take?

SEO and AI search

More and more people ask ChatGPT and Perplexity, and Google shows AI Overviews and AI Mode above the ordinary results. Does that mean SEO is dead? No. AI search largely rests on the same foundation: pages that can be found, understood and trusted.

Google says there are no separate requirements to appear in AI Overviews or AI Mode, and that the same fundamental SEO applies (Google Search Central). Read more in Google AI Overviews and about our work on AI visibility.

7 SEO tips to get started

1. Connect Google Search Console. It is free and shows which searches you already appear for, and whether anything is wrong.
2. Find out what customers search for. Write down how customers describe their problem, not how you describe your service.
3. Give each important service its own page, with one clear main keyword.
4. Write good titles and descriptions. The title is the first thing people see in the results.
5. Answer directly. Start pages with a short, clear answer. It helps both readers and AI search.
6. Make the site fast, especially on mobile.
7. Link internally between pages that belong together.

Do it yourself or get help?

You can do much of the groundwork yourself. It often pays to get help when competition is tough, when the site has technical problems, or when your time is better spent on the core business. If you are curious about how the machinery works, read How does SEO work?