PBN (Private Blog Network)

A private blog network is a set of websites somebody controls for the purpose of linking to another site and pushing it up the rankings. The classic recipe is to buy expired domains that still carry backlinks from their previous life, put thin content on each one, and point links at the site that actually makes money.

PBN builders are a real slice of the expired-domain market. They're the buyers paying for backlink profiles rather than names, which is why a forgettable domain with strong Majestic or Ahrefs metrics can sell for more than a nicer-sounding one with no history.

Google treats it as a link scheme and periodically deindexes networks wholesale. If you're selling into that market, fine, it's their risk. If you're buying an aged domain for a real business, check whether it was part of one, because a manual penalty travels with the domain.