A PBN number is the total count of websites or domains that make up a Private Blog Network. A PBN is a collection of sites owned by one person or entity, built primarily to create backlinks pointing to a main money site. The number of domains in a PBN varies widely depending on budget, risk tolerance, and SEO goals. Small operators might run 5–10 domains. Mid-tier setups often sit between 20–50. Large-scale PBN operators sometimes manage hundreds of domains, though that dramatically increases cost and detection risk. Each domain in a PBN should ideally have its own hosting footprint, unique IP address, different registrar details, and distinct content to avoid leaving patterns Google can identify. The operational cost per domain typically runs $50–150 CAD annually when you factor in hosting, domain renewal, and minimal content. So a 20-domain PBN costs roughly $1,000–3,000 per year just to keep alive, before considering the upfront cost of acquiring aged or expired domains with existing authority. The bigger the PBN number, the more links you can build to your money site, but also the harder it becomes to maintain quality and avoid footprints. Google's spam algorithms specifically target PBNs by looking for shared hosting IPs, WHOIS patterns, identical themes, thin content, and unnatural outbound link profiles. A small, well-maintained PBN of 10–15 domains with real content and varied hosting can be safer than a bloated 100-domain network with obvious patterns. Ottawa SEO Inc. does not build or recommend PBNs for client work. The risk-reward math rarely justifies it in 2025. One manual action can deindex the entire network and any site it links to. We focus instead on earned editorial links, digital PR, and strategic content partnerships that carry zero penalty risk and compound in value over time. If you're evaluating a PBN, understand that the number matters far less than the operational security and content quality behind each domain.