Link building glossary

Private blog network (PBN)

A private blog network (PBN) is a group of websites, often rebuilt on expired domains that still carry backlinks, run by one owner or seller mainly to link to other sites and lift their rankings. Google treats PBN links as link spam because they exist to manipulate search results, not to serve readers.

Reviewed by Gareth Hoyle, Managing Director
Last reviewed 31 October 2026

How does a PBN work?

The operator buys expired domains that already have links from other sites, puts thin content back on them and adds links to a target site, either their own or a client's paying per link. The network is private only in the sense that the owner tries to hide the connection between the sites, using different hosting, themes and registration details, because it stops working once Google spots the pattern.

Why does Google treat PBNs as link spam?

Google's spam policies do not use the term PBN, but they cover it. Link spam is creating links to or from a site primarily to manipulate rankings, and the examples include buying or selling links that pass ranking credit and creating low-value content mainly to manipulate linking signals. Since 5 March 2024, the expired domain abuse policy also covers buying an expired domain and repurposing it mainly to manipulate rankings with content of little value to users.

Detection has improved over time. In September 2014 Google sent large numbers of manual actions to sites in PBNs, many of which were removed from the index. Since the December 2022 link spam update, SpamBrain can detect sites used to pass outgoing links, and Google says the credit those links pass is lost.

What is the risk for the site being linked to?

The usual outcome is that the links are ignored and the money is wasted. The worse outcome is an Unnatural links to your site manual action. If a previous supplier used a PBN, ask for the links to be removed and disavow those that remain.

Example

A seller offers high-DR guest posts for £40 each. The sites share a template, publish on unrelated topics side by side, and every article links out to two or three commercial sites. Those are typical signs of a PBN.