Gray hat SEO: eight guides, eight different lists of techniques

Gray hat SEO, also spelled grey hat SEO, is a label for search engine optimisation techniques that the person using the label places between "white hat" and "black hat". It is a label, not a fixed list.

We read eight guides to gray hat SEO in full on 3 October 2026. Seven of them carry dates, from May 2020 to September 2026, and no two of the eight list the same set of techniques. One technique, cloaking, is listed under gray hat by two of the guides and under black hat by three. This page sets out how named sources define the term, where it comes from, which guides list which techniques, how the most-listed techniques work, and what we look at when we place a link.

What is gray hat SEO (grey hat SEO)?

There is no single definition of gray hat SEO, and the people who write about the term say so themselves.

Helen Pollitt, now Head of SEO at Getty Images, wrote in Search Engine Journal on 4 May 2020: "As with a lot of SEO, there are differing opinions on what gray hat SEO is." In the same article she sorts the definitions she found in other articles into two kinds. The first: "It’s a mixture of white hat and black hat techniques." The second: "It’s a tactic that is currently either white or black hat but with changes to the ways search engines work could become the opposite in the future."

Bob Meinke, writing for Bruce Clay, Inc. on 23 November 2011, collected definitions too: "I found several slightly overlapping definitions:" One of the definitions he lists: "Techniques that are somewhat deceptive yet not specifically disallowed by search engines’ published guidelines – but may someday be." The title of his article gives his position on the term: There’s No Such Thing as “Gray Hat” SEO.

Set side by side, these are three different things. One describes a mixture of two other labels. One describes a technique whose label can change over time. One describes somewhat deceptive techniques that published guidelines do not yet specifically rule out.

A technique can meet one of these definitions and not another. Meinke was writing in 2011 and Pollitt in 2020, and the dated guides in the table further down, from 2020 to 2026, show the same disagreement still running.

Pollitt also gives her own view of the labels: "Essentially, the use of white, black, and gray hat terminology is arbitrary."

Where the term gray hat comes from

The hat colours come from film westerns. Merriam-Webster's entry for "white hat", last updated on 4 November 2025, traces the term to the white hats worn by law-abiding characters in westerns and dates its first known use to 1965.

"Gray hat" came later, and from computer security rather than search engines. In Wearing Many Hats, a Data & Society report from January 2022 on the history of professional security hacking, Matt Goerzen and Gabriella Coleman write: "“Gray hat,” for its part, was a more pointed linguistic intervention introduced by the L0pht into mainstream discourse in 1999." The L0pht was a hacker group in Boston. The authors add: "We were unable to locate any reference to gray hat prior to this period and independent of the L0pht."

In search engine optimisation, the earliest use we found is from 2004: on 16 April 2004, Search Engine Roundtable ran a post titled Are you White or Black: Gray Hat SEO. A post on the blog Blue Hat SEO dated 3 June 2007 asks what gray hat SEO is, and says most people define it as a site that uses questionable tactics. On 21 August 2007, Mark Jackson of Vizion Interactive wrote in Search Engine Watch: "Search engine optimizers will often refer to themselves as white hat, gray hat, or black hat." Both 2007 pieces write about the label as one already in use.

So in the earliest uses we found, the label named people and sites, not a list of techniques. The Data & Society report says the L0pht began to call itself gray hat, and Jackson wrote of SEOs who call themselves gray hat. By May 2020, the date of the earliest dated guide below, the label had been in use in search engine optimisation for more than a decade.

Grey hat SEO techniques: which guides list which

We read eight guides in full on 3 October 2026 and noted which techniques each one lists under its gray hat or grey hat heading. The eight are the Ahrefs glossary entry (undated); Helen Pollitt in Search Engine Journal (4 May 2020); Dofollow (24 April 2024); Serpzilla (14 June 2024); Seopital (22 January 2025); Appskystar (updated 13 June 2025); Respona (17 June 2026); and SearchSEO (updated 15 September 2026). The table takes twelve techniques from those lists. It is a count of eight guides, not a measure of what SEOs do, and the last column shows where one of the same eight guides puts the technique under black hat instead.

Which of the eight guides list each technique under gray hat, and which file the same technique under black hat.

No technique is on all eight lists. Of the twelve, keyword stuffing has the highest count, seven of eight. Private blog networks and spun or duplicated content follow at six, and seven of the twelve appear on at least four of the lists. Three of the twelve are on one list only: doorway pages, negative SEO, and comment and forum links.

The same technique gets both labels. Cloaking is listed under gray hat in two guides and under black hat in three. Private blog networks are listed under gray hat in six guides and under black hat in Pollitt's, and Respona lists them under both. Seopital and SearchSEO each list keyword stuffing under both labels in the same guide. Doorway pages are listed under gray hat by SearchSEO and under black hat by Pollitt and Dofollow, and negative SEO is listed under gray hat by Ahrefs and under black hat by Dofollow.

Pollitt's own gray hat examples are none of the twelve: she lists content created purely to gain links and content written purely to rank a page. Serpzilla's guide of 14 June 2024 makes the same point itself: it says there is no definite list of these techniques, and that most marketers will not agree on one.

How the most-listed techniques work

Below are five of the techniques listed by at least half of the eight guides, described by what they are.

Private blog networks

A private blog network is a group of websites owned by the same person or company, used to link to sites that owner chooses. A link farm is a group of sites that link to one another. Because one owner controls every site in the network, that owner decides where each link sits and what it points at. We go deeper in our guides to private blog networks and the link farm.

Keyword stuffing

Keyword stuffing is repeating a search term on a page many more times than the sentence needs. Keyword density is the measure people use for it: the share of a page's words that the term makes up.

Spun or duplicated content

Article spinning takes an existing article and produces new versions of it by swapping words, phrases or sentence structures, by hand or with software. The result is several texts where there was one, each different enough from the original to read as a separate article. Duplicated content is the same text published at more than one address.

Expired domains

When a domain's registration lapses, someone else can register it. The new owner gets the name and, with it, the links that other sites still point at it. The guides describe two uses: rebuilding a site on the domain, or redirecting it to another site. A redirect of this kind is a 301: in RFC 9110, the HTTP standard published in June 2022, the 301 (Moved Permanently) status code indicates that the resource has been assigned a new permanent address.

Link exchanges

Two sites agree to link to each other. Reporter Outreach, a link building agency, surveyed 500 SEO professionals in the first quarter of 2026: 43.8% said they use link exchanges. That figure is the survey's count of its own respondents. Our guide to reciprocal links covers the practice in more detail.

What we look at when we place a link

When we choose a publisher for Guest Posts or Curated Links, we weigh indexed pages, organic traffic and its trend, Moz DA, Ahrefs DR, referring domains and the strength of the link profile together, and each placement is on a real, independently owned website. We reject outright sites with private blog network or link farm footprints, manipulated traffic or metrics, expired-domain abuse, and thin, spun or low-quality content.

After publication we check that the page is live, that the link is in the body copy, that the anchor and target URL match the order and that the page is indexable, and only then is the URL reported to the dashboard. That check is part of our quality assurance process, and each link carries 12-month replacement cover. If a delivered link is removed or its page is taken down inside those 12 months, we replace it like for like.

Frequently asked questions

What is gray hat SEO?

Gray hat SEO is a label for search engine optimisation techniques that the person using it places between white hat and black hat. Named sources define it differently: as a mixture of the two, as a technique whose label may change over time, or as somewhat deceptive techniques that published guidelines do not yet specifically rule out. It is a label, not a fixed list.

Is it gray hat SEO or grey hat SEO?

They are the same term, with the same meaning, in two spellings. Gray is the American spelling and grey the British one. The guides we read use both, and one of them also shortens it to gray SEO. This page uses gray in its own sentences and keeps grey where a heading or a source carries it.

What are examples of grey hat SEO techniques?

Of the twelve gray hat SEO techniques we counted in eight guides on 3 October 2026, keyword stuffing was listed most, in seven of the eight. Private blog networks and spun or duplicated content came next, each in six, then expired domains and automated or AI-written content, each in five. No technique was on all eight lists.

Where does the term gray hat come from?

The hat colours come from film westerns. A Data & Society report traces gray hat to the hacker group the L0pht in 1999, in computer security. The earliest use in search engine optimisation we found dates from 16 April 2004, in a post title on Search Engine Roundtable.

Who decides what counts as gray hat SEO?

Nobody does. There is no body that sets the list, so each guide draws its own. In the eight guides we read, the same technique appears under gray hat in one guide and under black hat in another. Helen Pollitt, writing in Search Engine Journal in 2020, calls the use of the terminology arbitrary.