There's no registry or official system that assigns you a PBN number. The term simply means how many domains you've built into your private blog network. You create that number yourself by acquiring expired domains, aged domains at auction, or registering new ones, then hosting them as separate entities to link back to your money sites. Small operators typically start with 5–10 domains to test whether the ROI justifies the hosting and content costs. Each domain needs unique hosting (different IPs, ideally different C-blocks), separate registrar details if you want to avoid footprints, and enough content to look like a real site. At Ottawa SEO Inc., we've seen setups ranging from solo consultants running 8–12 domains to aggressive affiliate players managing 100+ across multiple niches. The practical ceiling depends on three factors: budget (hosting 50 domains on quality infrastructure costs $150–400 CAD/month), content production (each site needs 10–30 posts to avoid thin-site flags), and risk tolerance (larger networks create bigger penalties if Google connects the dots). You also need to track which PBN site links to which money site, so most people cap out where spreadsheet management becomes unmanageable, usually 30–50 domains for one person. Keep in mind that PBNs violate Google's Webmaster Guidelines. If the network gets detected through shared analytics codes, similar WHOIS data, identical themes, or interlinking patterns, you lose all the domains and any money sites they boosted. That's why some SEOs prefer the term "domain portfolio" and use the sites for legitimate content with occasional contextual links, which lowers risk but also lowers control. If you're asking because you want to buy links from someone else's PBN, they'll typically quote you per-link rather than disclose their total number of domains. Expect $80–300 CAD per permanent link depending on the domain's authority and niche relevance.