Éric St-Cyr

A story of reinvention

Éric St-Cyr was born in a small village near Trois-Rivières, Québec. His first career took him into the highest levels of international finance — first with a Canadian bank, then with a firm in the Cayman Islands — a chapter that ended in a very public collapse and cost him nearly everything. He tells that story candidly in his 2016 memoir, À l'ombre du soleil, a gripping account of high finance, offshore banking and a hard fall that reads, as its own description puts it, like a good thriller.

What matters most is what came next. In his fifties, with everything gone, Éric started over — this time in search engine optimization. He built ProStar SEO from the ground up and, over more than a decade, turned it into a group of specialized agencies. That lived experience of loss and rebuilding is exactly why he approaches SEO the way he does: no shortcuts, no false promises, and a relentless focus on results that can be measured.

Read the book — on the house

Éric owns the rights to À l'ombre du soleil and would rather people read it than pay for it. Want the full, unvarnished story of the fall and the rebuild? Email Éric for a free copy and he'll send it your way.

What Éric has built

Today Éric leads a family of niche SEO agencies, each serving a demanding, competitive vertical:

• ProStar SEO — the flagship, multi-industry SEO agency.
• Agence SEO Paris — French-market SEO built on Contextual Density.
• Plastic Surgery SEO — for cosmetic surgeons and clinics.
• Med SEO — healthcare and medical practices.
• Dentist SEO — dental and orthodontic practices.
• SEO for Contractors — home services and construction.
• CannabisSEO.ai — this agency, focused entirely on cannabis, CBD and dispensary SEO.

Across those brands, Éric and his team serve more than 100 clients in every industry, from single-location shops to national brands. Their largest client earns over 10 million organic clicks per month — the kind of scale only compounding, well-engineered SEO can produce.

The method: Contextual Density

Éric is the creator of Contextual Density, the measured, benchmark-driven methodology behind every page his agencies build. Rather than guess at "quality," he scripts the contextual density of the pages already ranking for a keyword, then engineers new pages to cover the topic roughly ten percent more thoroughly — a standard he can validate page by page. It is SEO treated as engineering, forged in the web's most competitive, ad-restricted markets: cannabis and CBD, gambling, cosmetic surgery and more.

Areas of expertise

• Cannabis & CBD SEO — dispensary, CBD and marijuana search in a compliance-heavy, YMYL category.
• Local SEO — Google Business Profile, the map pack and "near me" visibility.
• Technical SEO — crawlability, Core Web Vitals, schema markup and architecture.
• Link building — compliance-safe authority in stigmatized industries.
• AI search (GEO/AEO) — getting brands cited by ChatGPT, Perplexity and Google AI Overviews.

Philosophy

Éric's core belief is simple: Google counts, it does not read — so quality has to be made measurable. Having rebuilt from nothing, he is candid about what SEO can and cannot promise (no one guarantees the number-one position), works without long-term contracts, and insists that clients understand every action taken on their site. That transparent, scientific, hard-won approach is what CannabisSEO.ai brings to the cannabis industry.

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