Can anybody tell me what is PBN in SEO?

commented: I worry that FuGenX Technologies is going to last long. -3
commented: Too lazy to google? -1

Private blog networks (PBNs) are the go-to link building tactic for grey hat SEOs.
The principle of building a PBN network usually looks like this:
-Registrated or purchased drop domains, which have certain indicators of credibility.
-A site is created, usually based on WordPress
-Add posts with links to promoted sites