Craig Campbell is an SEO consultant based in Glasgow, Scotland with 16 years of experience in the industry. He offers training and consultancy services to help clients avoid mistakes he made over the years as a freelancer and agency owner. While private blog networks (PBNs) can be an effective link building technique, they require careful execution to avoid appearing spammy or violating search engine guidelines. Campbell recommends treating PBN sites like real websites by adding new original content regularly and building natural backlinks over time rather than relying on low-quality tactics.