The three pillars of SEO: technical, content and authority

If you want to understand SEO, the best place to start is the three pillars every good strategy rests on: technical SEO, content and authority. They reinforce each other. A technically perfect site without good content won't rank, and neither will great content that search engines can't read. Let's go through them one by one.

1. Technical SEO: the foundation

Technical SEO ensures that search engines and AI crawlers can discover, fetch, read and understand your website. It is the least visible pillar, but often the most decisive. Key elements include:

• Crawlability and indexing: can bots reach all important pages, and are the wrong pages kept out of the index?
• Site speed and Core Web Vitals: does your site load quickly and stably, especially on mobile?
• Mobile-friendliness: Google evaluates websites based on their mobile version (mobile-first indexing).
• Structure and internal linking: a logical architecture helps visitors and search engines see how pages relate.
• Structured data: schema markup explains what a page contains in a standardised format.
• Canonicals and hreflang: prevent duplicate content and show the right version per country or language.

Want to go deeper? See the technical SEO training.

2. Content: answering the question

Search engines want to give the searcher the best possible answer, so content is all about relevance: does your page match what someone really wants to know or do? That starts with keyword research, but it's about far more than repeating keywords. Good SEO content:

• matches search intent (informational, comparative or transactional);
• is complete, up to date and factually correct;
• shows who wrote it and why they know the subject (E-E-A-T: experience, expertise, authoritativeness and trustworthiness);
• is easy to read, with clear headings and short paragraphs;
• contains clear, quotable answers that AI models can pick up.

More in the content training.

3. Authority: the trust of others

Authority is about how the rest of the web sees you. Links from relevant, reputable websites have been an important ranking factor since Google's early days: every good link acts as a recommendation. Unlinked brand mentions, reviews and your reputation count for more and more, especially in AI search. Sustainable link building is about quality and relevance, not volume. Buying links or joining link networks tends to cause problems rather than results in the long run.

More in the link building training.

Keeping the pillars in balance

Every website has its own weakest link. An online shop with thousands of products often struggles with technical issues, a service business with content or authority. A good SEO strategy therefore starts by assessing all three and invests first where the gains are biggest.