A Private Blog Network (PBN) is a network of websites that only exist to link to a central site. This is done in order to influence the authority of this site in search.

What are private blog networks and what do they mean for SEO?
A Private Blogging Network (PBN) uses a network of websites to create links to a specific or central site and influence its authority. Links generated through this network increase the authority of the central site by improving its ranking. This ...