SEO Basics

SEO stands for search engine optimisation. It is the practice of making a website more visible in search results, so people can find it without you paying for each visit.

What is SEO?

When someone searches on Google, the engine decides which pages to show and in what order. That decision is based on hundreds of signals: how relevant the content is to the query, how trustworthy the site appears, how fast and usable the pages are, and how many reputable sites link to them. SEO is the discipline of understanding those signals and improving them.

The goal is to earn unpaid, or organic, positions in search results. Organic results sit below any paid adverts and get the majority of clicks. Unlike paid search, where visibility stops the moment a campaign ends, organic rankings built through SEO continue to drive traffic as long as the content stays relevant.

What SEO is not

SEO is not about tricking search engines. The tactics that gamed early algorithms have been closed off over time. What remains is more straightforward: create genuinely useful content, ensure the site is technically sound, and build a reputation worth citing.

It is also not a one-time fix. Search engines update their algorithms regularly, competitors improve their own sites, and what people search for shifts over time. SEO is an ongoing activity, not a project with an end date.

What are the four types of SEO?

SEO splits into four main disciplines:

• On-page SEO covers the content and signals on each page: title tags, headings, the depth and accuracy of the writing, internal links, and structured data.
• Technical SEO covers the infrastructure of the site: how quickly pages load, whether search engines can crawl and index everything, mobile usability, and site architecture.
• Off-page SEO covers what the rest of the internet says about the site, primarily through links from other websites, which act as votes of confidence.
• Local SEO covers visibility for businesses that serve a specific geography, including Google Business Profile, local pack rankings, and citations.

A fifth area has emerged alongside these: optimising for AI-powered answer engines. AI search retrieves and cites content differently from traditional results pages, and the signals that earn citations there overlap significantly with good SEO practice. Google’s search ecosystem, spanning organic results, Discover, News, Shopping, AI Overviews, AI Mode, and Voice Search, means understanding which types of SEO apply to each surface is worth establishing early.

Core SEO topics

New to SEO? Start with How to learn SEO, a structured path that sequences these topics in the order they build on each other. The topics below group into five areas: the foundations, how Google ranks and updates, the wider search landscape, the white-hat and black-hat spectrum, and the practical starting points.

Foundations

• How search engines work. The crawl, render, and index pipeline that determines whether a page can appear in results at all.
• What is organic search?. The difference between paid and unpaid results, and why organic positions have lasting value beyond individual campaigns.
• Types of SEO explained. How on-page, technical, off-page, and local SEO fit together as a discipline.
• Semantic search. How search engines interpret meaning and context rather than matching keywords literally.

How Google ranks and updates

• How does the Google algorithm work?. The core ranking signals Google uses to evaluate relevance, quality, and authority.
• What are Google core updates?. What core updates change, how often they occur, and what to do if rankings drop after one.
• Google algorithm updates. The taxonomy of core updates, spam updates, and the Helpful Content system: what each targets, how to identify which type affected your site, and the correct response for each.

The search landscape

• Google’s search ecosystem. The full range of Google surfaces (organic, Discover, News, Shopping, AI Overviews, AI Mode, Voice) and how each differs.
• Bing and the Microsoft search ecosystem. How Bing differs from Google, and what visibility on Copilot and ChatGPT Search requires.
• Bing ranking factors. How Bing’s ranking signals differ from Google’s, chiefly the social and engagement signals it is more open about, and what to adjust for visibility across Bing, Copilot, and ChatGPT Search.

White hat, black hat, and risks

• White-hat SEO. The principles that align with search engine guidelines and build sustainable rankings.
• Black-hat SEO. The tactics that violate search engine guidelines and the ranking penalties they risk.
• Parasite SEO. Publishing on a high-authority third-party domain to borrow its ranking signals, and why Google’s site reputation abuse policy now penalises it.
• Negative SEO. The deliberate attempt to harm a competitor’s rankings: which attack vectors still work, and how to defend against them.

Practical foundations

• How long does SEO take?. Realistic timelines for ranking movement, and the factors that accelerate or delay results.
• SEO auditing. A systematic approach to identifying the technical, content, and off-page issues limiting a site’s visibility.
• Choosing a domain name. How domain choice affects brand recognition, trust signals, and long-term SEO.