Research roundup · PBN & expired domains

PBN backlinks explained: how they work and how Google finds them

PBN backlinks are links from sites one owner secretly controls. Learn how they work, what they cost and how Google's SpamBrain spots them.

By iSEOHive Editorial · Published 12 Nov 2026 · Last updated 12 Nov 2026 · 4 min read

Key takeaways

PBN backlinks come from sites one owner controls, usually built on expired domains, and exist to pass ranking signals to a target site.
Google lists link spam and expired domain abuse in its spam policies. Its March 2024 post used casino content on an old medical site as an example.
Detection speed is disputed. Sources say hours or days, and none we found cites Google's own timing.
Quoted prices run from $1 to $500 per link. Most figures come from sellers, so treat them as claims, not benchmarks.

The short answer

PBN backlinks are links from a group of sites that one owner secretly controls, built to lift another site in Google. Google's spam policies treat this kind of link as link spam. Its March 2024 blog post says violating sites may rank lower or not appear at all. Relevant Audience says PBNs are not illegal, but they break Google's rules.

What are PBN backlinks?

Menford describes PBN backlinks as links from a private blog network. That is a set of seemingly independent blogs, secretly owned by one person or organisation. SearchOS calls the target the "money site". The network exists to push links to it.

Most networks sit on expired domains. Link Doctor says builders buy expired or aged domains that already have backlinks, rebuild the sites and link them to the main site. Dofollow says new domains are slow and costly to build, so old ones with authority are attractive.

RhinoRank draws the key line. A PBN link is placed because the owner controls the site. An editor did not choose it as a reference.

The typical shape, as these sources describe it:

An expired domain with existing backlinks is bought.
A site is rebuilt on it, often with thin content.
Links point from that site to the target page.
Many such sites repeat the pattern.

How does Google find a private blog network?

Google's side is policy plus automation. Relevant Audience reports that Google's December 2022 link spam update used SpamBrain, its AI-based spam system. It was aimed at both sites buying links and sites passing them. The same page says Google relies on automated systems and, where needed, human review.

Sources list the footprints these systems may use:

Screaming Cat says a group of sites that link only to each other and one money site is an obvious PBN footprint.
HighDA PBN Links, a link-selling site, lists shared hosting subnets, shared nameservers, shared analytics accounts and identical themes.
Rankigaming says casino networks are spotted through common WHOIS data, IP blocks and templates.

Google's own March 2024 post covers the domain side. It defines expired domain abuse as repurposing a lapsed domain mainly to manipulate rankings with low-value content. Its example is a former medical site turned into low-quality casino content.

Outcomes differ. HighDA PBN Links says detection often brings no Search Console alert. The links just stop passing value. Milodomain says serious cases bring a manual action, shown in Search Console.

Do PBN links still work?

Sometimes, briefly. Linkbuilder.io says they can still produce short-term gains, mainly in low-competition niches. Backlinks Matters says they are no longer a reliable growth source.

The failure mode is all at once. Linkpanda says that when a network is deindexed, every link disappears together. The target can then lose a big share of its link profile overnight.

Recovery costs are also quoted. SEO.Domains cites DomCop figures of $312 to $9,380 per penalised property. We could not check DomCop's method.

How much do PBN links cost?

Prices vary widely, and most figures come from sellers or agencies with something to sell. The table puts several side by side. Currencies are mixed and the dates differ.

Source	What it prices	Figure quoted
Respona, as cited by RhinoRank (8 July 2026)	Sales pitch for one PBN link	$1 to $5
Editorial.link	Freelancer marketplace listings, per link	$15 to $150
Milodomain	Low-cost PBN link	EUR 20 to 80
Hetneo's Links	Quality-network PBN link	$100 to $500
Ahrefs, as cited by SEO.Domains	Average niche edit on an independent page	$361.44
Milodomain	Sponsored article on a DR 50+ media site	EUR 500 to 1,500
PBNBuild press release on OpenPR	Building one site, domain billed separately	$150 to $180
LinkBuilder, same press release	Building one site	$300 to $550
Editorial.link	One expired domain, 50+ referring domains, DR30+	$2,000 to $3,000

The spread says something. A cheap link is cheap because many buyers share the same network. Hetneo's Links puts a 20-site network at $500 to $2,000 or more per month to run. That is a seller's estimate.

Why is the risk higher in iGaming?

Google chose casino content for its expired domain example. That does not prove gambling sites are targeted more often. It does show the vertical is in Google's own illustrations.

Mother of Ads says PBNs remain part of the commercial iGaming SEO market, and their risk profile is contested. It advises weighing PBN exposure as a business risk. A ranking is worth less if it depends on assets you cannot audit.

Compliance adds another layer. Outreach Desk says a link from a site that breaches UK Gambling Commission rules can create compliance exposure for a licensed operator. Gambling and advertising law differs by country. This article reports what the sources say and is not legal advice.

What we could not confirm

Google's exact wording. Search results gave us Google's March 2024 blog post and third-party quotes of the spam policy. We did not read the full policy page.
Whether Google names PBNs. Dofollow says Google's guidelines do not state it outright. Linkpanda says they do. Sources disagree.
Detection speed. Blue Tree Digital says devaluation can start within hours. Links-Stream says filters can fire within days. Neither cites Google's own timing.
Catch rates. We found no reliable data on how many networks are caught. Some pages quote precise lifespans and percentages without showing method. We left them out.
Prices. The figures are seller claims or agency estimates. We found no independent price survey.
iGaming penalty rates. We found no data comparing penalties for gambling sites against other niches.

Questions and answers

What does PBN stand for in SEO?

PBN stands for private blog network. Link Doctor and Menford both describe it as a group of sites owned or controlled by one person or company and used to link to a main site.

Are PBN backlinks illegal?

Relevant Audience says PBNs are not illegal but they violate Google Search's spam policies. Gambling and advertising rules differ by country. This is not legal advice.

Can Google detect a PBN?

Sources say yes. Relevant Audience reports Google's December 2022 link spam update used SpamBrain to find sites buying links and sites passing them. How reliably it catches every network is not public.

Do PBN backlinks still work?

Linkbuilder.io says they can give short-term gains, mainly in low-competition niches. Backlinks Matters says they are no longer a reliable source of growth.