Link spam
Google's spam policy category covering links intended to manipulate rankings: buying or selling links, excessive exchanges, automated link…
LinksPBN
Private blog network
A set of websites, often built on expired domains, controlled by one party for the purpose of passing links to money sites; a clear link spam violation.
In full
PBNs attempt to simulate independent endorsement while being centrally owned, and are detectable through hosting, registration, template, content and interlinking patterns. Google's link spam systems and the expired domain abuse policy both bear on them, and detection typically nullifies the links rather than merely discounting them. The economics have deteriorated as detection improved and expired-domain reuse became an explicit policy target.
Example
Twenty niche 'review' sites on the same hosting, all published within one month, linking to the same three commercial domains.
Related terms
Expired domain abuse
Buying an expired domain and repurposing it to host unrelated low-value content in order to inherit its accumulated ranking signals.
Link graph
The network of all pages as nodes and hyperlinks as edges, over which link-based ranking algorithms such as PageRank are computed.
Manual action
A demotion or removal applied by a human reviewer at Google for a spam policy violation, reported in Search Console with a reconsideration…
SpamBrain
Google's AI-based spam prevention system, used to detect spam at crawl and ranking time and to identify and neutralise unnatural links.