SEO: the guide to organic search optimization

What is SEO?

SEO stands for Search Engine Optimization, also called organic search optimization. For Google, it means helping search engines understand your content and helping users find your site (Google’s “SEO Starter Guide”, accessed on September 26, 2026).

SEO targets so-called organic results: those you do not pay for per click. This is what sets it apart from SEA, advertising on search engines, where the advertiser buys its place at auction. The two levers often complement each other; how they fit together is detailed in our page on SEO and SEA together.

For a business, the benefit is simple. A well-ranked page attracts visitors as long as it stays relevant, with no cost per click. On the other hand, the effects take time and no service provider can guarantee a position.

Why do SEO?

Organic search answers a demand that already exists: the user searches, you appear. This is what makes it a distinct acquisition lever, to be compared with advertising or social media.

Strength	Limit to be aware of
No cost per click: traffic does not stop when the budget stops	The work (technical, content, links) has a cost, in-house or external
Visitors who have expressed a specific need	Effects are measured in months, rarely in days
A lasting asset: a useful page can rank for years	No position is guaranteed, Google’s rules change
Demand data you can reuse (content, SEA, product)	Competitors work on the same queries

SEO is poorly suited to a need for immediate visibility, such as a launch or a time-limited campaign. There, advertising takes over. It is well suited to a business built for the long term, whose customers search on Google.

How does a search engine like Google work?

Google describes three stages (“How Google Search works” documentation, accessed on September 26, 2026):

• Crawling: robots, including Googlebot, discover pages by following links and sitemaps, then download them.
• Indexing: Google analyzes the text, images and tags, and decides whether the page enters its index.
• Serving search results: for each query, the ranking systems select and order the most useful pages.

The same page states that Google accepts no payment to crawl a site more often or to improve its ranking. Each stage can block the next: a page that is not crawled will never be indexed, a page that is not indexed will never be ranked.

These mechanisms, along with the basic vocabulary (query, SERP, intent, index), are developed in our page on the Google algorithm.

What are the 3 pillars of SEO?

Most practitioners split organic search optimization into three pillars. This split is an industry convention, not a classification published by Google. It still helps to divide the work and make a diagnosis.

Pillar	Question asked	Examples of workstreams
Technical	Can Google crawl, render and index my pages?	robots.txt, sitemap, redirects, speed, JavaScript rendering
Content	Do my pages answer the query better than the others?	keywords, intent, title, heading structure, evidence
Authority	Do other sites refer to mine?	backlinks, brand mentions, press relations

Two dimensions run across the three pillars: the site architecture, which distributes internal links, and measurement, which tells you what works. The following sections go through each workstream and link to its dedicated page.

Technical SEO: a crawlable, indexable and fast site

Technical SEO checks three things, in this order: is the site crawlable, is it indexable, and is the technical experience up to standard? As long as the first question is not settled, working on the other two is pointless.

For experience, Google tracks the Core Web Vitals. They are measured on real visits, at the 75th percentile, separately on mobile and desktop (web.dev, “Web Vitals”, accessed on September 26, 2026):

Metric	What it measures	“Good” threshold
LCP	Display of the largest visible element	2.5 s or less
INP	Responsiveness to interactions	200 ms or less
CLS	Visual stability of the layout	0.1 or less

Common blockers to check first:

• a Disallow directive inherited from a staging site that blocks entire directories;
• important pages set to noindex or canonicalized to another URL;
• redirect chains and internal links to pages returning a 404 error;
• content displayed only through JavaScript, which the robot does not always see on the first pass.

Robots.txt, sitemaps, canonicals, JavaScript and performance are covered in our technical SEO section.

Content and semantics: answering search intent

A page ranks for a query when it answers it better than the others. The starting point is therefore not the keyword but the intent: does the user want a definition, a comparison, a price, a service provider? The SERP shows it. Before writing, look at the type of pages Google already displays.

Google asks for “helpful, reliable, people-first” content (Google, “Creating helpful content”, accessed on September 26, 2026). It offers a self-assessment grid. Its criteria cover originality, the author’s visible expertise and the value added compared with pages that already rank.

• one page, one intent: two pages on the same query compete with each other (cannibalization);
• a title of 50 to 60 characters, with the query at the start;
• headings that sum up the page on their own;
• sourced and dated figures, an identified author.

Formats, editorial strategy, semantics and updates are detailed in our guide to SEO content.

Internal linking and site structure: organizing the site and its links

Internal links play two roles: they let robots discover pages and they show which ones matter. Google only reliably follows links in an <a href> tag. It also recommends descriptive anchor text (Google, “Crawlable links”, accessed on September 26, 2026).

A healthy architecture keeps strategic pages a few clicks from the home page, with no orphan pages. Silos and semantic cocoons are practitioners’ methods, useful for structuring, but Google does not document them.

Depth, silos and step-by-step construction: see our guide to site structure.

Link building: building authority without risk

Link building means getting links from other sites. Practitioners believe that a link placed in the body text of a page on the same topic carries more weight than a footer link; Google publishes no scale. The nofollow, sponsored and ugc attributes tell Google that a link should not pass authority.

Before getting a link, look at the page that will carry it rather than the domain. Does it cover your topic? Does it get visits? Is the link placed in the body text? Authority scores from third-party tools help sort a list, but none reproduces Google’s calculation.

Qualifying a source site, running a campaign, reading the risks: that is the subject of link building and authority.

Local SEO: being visible near your customers

For a business that welcomes customers or works within an area, local SEO matters as much as the site. Google ranks business profiles on three criteria: relevance, distance and prominence (Google Business Profile Help, accessed on September 26, 2026).

• a complete business profile: correct primary category, opening hours, service area, photos;
• regular customer reviews, with a reply to each one, including negative reviews;
• identical contact details on the site, the profile and directories;
• one page per area or per location when the business justifies it, never duplicated pages city by city.

Prominence takes into account links to the business and the number of reviews. Google states that it is impossible to pay for a better local ranking. Business profile, reviews and local pages: see local SEO.

How do you measure and audit your SEO?

SEO that is not measured cannot be managed. Three sources are enough to start:

• Google Search Console: impressions, clicks, positions and indexing;
• an analytics tool: visits and conversions;
• a crawler, which explores the site like a robot and flags errors.

Question	Tool	Indicator
Are my pages indexed?	Search Console	page indexing report
For which queries am I visible?	Search Console	impressions, clicks, average position
Does organic traffic convert?	Analytics	organic channel conversions
Does the site have technical errors?	Crawler	HTTP status codes, depth, orphan pages

Components, steps and prioritization are brought together in our SEO audit method.

Is SEO being replaced by AI search engines?

No. Google now displays AI Overviews at the top of some searches, as well as a conversational AI Mode. According to Google, these features rely on its usual ranking and quality systems. No special markup or dedicated file is needed to appear in them (Google Search Central, AI optimization guide, updated on July 10, 2026).

What changes is the unit of measurement. You track position and clicks, but also being cited in a generated answer. This is the field of GEO (AI search optimization), which extends SEO without replacing it.

How to do SEO: where do you start?

Here is the order of work we apply, from diagnosis to follow-up:

1. Set the goal: leads, sales, awareness, and the indicator that measures it.
2. Check access: crawling and indexing of the pages that matter.
3. Map demand: queries, volumes, intents, one page per intent.
4. Optimize what exists: pages already on the second page of results are the fastest gains.
5. Produce and link: new content, internal links to strategic pages.
6. Measure and adjust: monthly review in Search Console, full review every quarter.

Timelines vary from one site to another: each site starts from a different state, and a past result does not guarantee the next one.

If you want an outside view of your site, our SEO services always start with a diagnosis.