Black hat backlinks: what the term means and which link techniques it names

Black hat backlinks is a label, also written blackhat backlinks or shortened to black hat links, that guides put on links built by certain techniques. Black hat link building is the same label applied to the work of building them. The guides do not all put the same techniques under the label. Across the nine dated pages we read for this guide, no link technique appears on more than five of the nine, so what the term covers depends on which page you read.

This guide sets out how three dated sources define the label, where the term comes from and which link techniques nine dated pages list under it. It then works through each listed technique with one dated or measured fact, explains what we check on a placement, and ends with a short FAQ. Every source is dated, and every count of techniques is a count of those nine pages.

What black hat backlinks and black hat link building mean

The two phrases are labels rather than fixed terms, and the dated sources that define them define them differently. Three dated definitions show how far apart the sources sit.

Webopedia's definition, written by Vangie Beal for the technology dictionary and last updated on 8 July 2021, reads: "black hat SEO refers to the use of aggressive SEO strategies, techniques and tactics that focus only on search engines and not a human audience". The page's examples under the label are on-page ones, such as keyword stuffing and invisible text, and Webopedia lists no link technique at all.

SEOptimer, an SEO audit software company, is the only one of the three whose page is about backlinks. On that page, dated 23 April 2019, Nicholas Godwin calls building black hat backlinks one common type of black hat SEO, next to keyword stuffing, content scraping and cloaking.

Nicholas Carroll takes a third line in an article written for the Encyclopedia of Library and Information Sciences, dated 16 February 2010 and archived by Hastings Research. Carroll records that technically sophisticated tactics are often equated with the black hat label, and a focus on high-quality content with the white hat label, and he notes that the two overlap substantially.

One dictionary, one software company and one encyclopedia author give three different descriptions, and only one of the three is about links. We offer no definition of our own. The more useful question is which techniques a given page puts under the label, and the table further down answers that question for nine dated pages.

Where the term comes from

The hat colours come from film westerns and passed into computer security before they reached search engine optimisation. That history is set out in our guide to gray hat SEO. How dated guides use the white hat and gray hat labels for link building is set out in white hat vs gray hat link building. We do not repeat either here. What follows are the dated uses found for this page. Where one is called the earliest, it is the earliest we found in this reading, not the first ever made, because earlier uses may sit in sources we did not read.

On 9 June 2003, Danny Sullivan wrote on Search Engine Watch that he had coined an earlier name for the same family of methods, search engine spamming, back in early 1996. That date belongs to his earlier term, not to the black hat label. On 16 April 2004, Search Engine Roundtable referred to a forum thread on black hat versus white hat SEO, the earliest dated use of the pair in SEO that we found. In December 2004, a session at the Search Engine Strategies conference in Chicago carried the title Black Hat, White Hat & Lots of Gray. BlackHatWorld, a forum that its Wikipedia entry (read on 4 October 2026) says has existed since 2005, began as a place to discuss search engine optimisation tips. On 16 March 2007, a post by Pete Watson-Wailes on the Moz blog carried Link Building the Black Hat Way in its title, the earliest dated use of the label for link building that we found. On 31 March 2008, CSO Online ran a feature by Scott Berinato on black hat SEOs.

Which link techniques nine dated pages list under black hat

Nine dated pages list different link techniques under the black hat label, and no link technique appears on more than five of the nine. The nine pages, in date order, are Nicholas Carroll's article for the Encyclopedia of Library and Information Sciences (16 February 2010), Search Engine Watch (Christopher Ratcliff, 11 October 2016), the Digital Marketing Institute (26 February 2018), SEOptimer (Nicholas Godwin, 23 April 2019), Webopedia (Vangie Beal, 8 July 2021), Forbes Advisor (Juliana Kenny, 28 June 2024), Bluehost (16 September 2025), IONOS (Sebastian Mews, 19 November 2025) and HubSpot (Alex Sventeckis, 29 January 2026). The group is a reference author, a trade publisher, a training body, four software or hosting companies' blogs, a dictionary and a business publisher.

A page counts as listing a technique when that page names the technique under its own black hat label, whether in a list, a heading or a definition. A page that names a technique only in passing, away from its black hat label, does not count as listing it. Each cell is taken from the page as we read it, and the date beside each page is the date that page shows. We read all nine pages on 4 October 2026, and every count in the table is a count of these nine pages, not a measure of the market. The table counts ten of the techniques the nine pages list, not every item on every page.

Link techniques listed under the black hat label by nine dated pages, read on 4 October 2026.

The nine pages differ more than they agree. No link technique is listed by more than five of the nine. Private blog networks, hidden links, and link farms or link wheels are each listed by four of the nine, which means five pages leave each of them out. Webopedia lists no link technique at all, and Carroll's article puts none of the link techniques in the table under the label. SEOptimer, the only one of the nine whose subject is backlinks, lists link wheels, tiered link building, expired domains and negative SEO, and names neither private blog networks nor link farms. Three other pages, Webopedia, Forbes Advisor and HubSpot, list hidden text but not hidden links.

The technique most of the nine share is keyword stuffing, listed by eight of the nine, and keyword stuffing is an on-page technique rather than a link technique. We cover keyword stuffing in our guide to keyword density. A reader who asks which techniques count as black hat link building gets a different list from each page, so the label on its own settles very little. The same techniques also move between labels: of the eight guides counted in our guide to gray hat SEO, six list private blog networks under that label.

How the listed link techniques work

Here is what each listed technique is, in plain mechanical terms, with one dated or measured fact where a study exists and a link to our own guide where we have one. Six short sections cover techniques from the table, a seventh covers one that none of the nine lists, and negative SEO follows in a single sentence.

Comment and forum posting

Five of the nine pages list links left in comment sections. The links can be posted by hand or by software that posts to many sites, and forum messages are used in the same way. Yuan Niu and co-authors studied this kind of posting in a 2007 study of forum posting presented at the NDSS symposium. One of their counts was of blogs on blog-hosting sites that had been set up to send visitors on to other sites, and they report: "On two blog sites, more than half (75% and 54% respectively) of the blogs are spam, and even on a major and reputably well maintained blog site, 8.1% of the blogs are spam". An earlier paper by Gilad Mishne, David Carmel and Ronny Lempel, from 2005, worked from 50 blog posts chosen because each carried a mix of comments, and classed 692 of the 1,024 comments on them as left for their links. Our own guide covers forum backlinks.

Private blog networks

Forbes Advisor's page of 28 June 2024 describes a private blog network as a set of sites that one person owns and links to each other. We found no dated study that measures private blog networks with a sample, so we give no figure for them here. Our own guide covers PBN backlinks.

Link farms and link wheels

Baoning Wu and Brian Davison of Lehigh University gave a definition in Wu and Davison's paper, presented in May 2005: "A link farm is a network of web sites which are densely connected with each other." For the paper's sample, the authors ran 412 queries and downloaded more than 2.1 million unique web pages. Those figures describe the authors' own dataset for that experiment, not a share of the web. The table above counts link farms and link wheels as a single row, and our own guide covers what a link farm is.

Hidden links

A hidden link is a link the reader cannot see. Zoltán Gyöngyi and Hector Garcia-Molina's taxonomy paper from 2005 describes text shown in the same colour as the page background, and notes that a link can be hidden by leaving out the anchor text. Search Engine Watch's page of 11 October 2016 adds text set to a font size of zero and text positioned off screen with CSS. Our own guide covers hidden links.

Link exchanges and tiered link building

A link exchange is an agreement between two sites to link to each other. Nicholas Carroll's 2010 article records that reciprocal links were the usual practice by the late 1990s, and that sites swapped them to send each other visitors rather than to move up in search results. Tiered link building, listed by SEOptimer alone among the nine pages, means building links to the pages that link to you. Our own guides cover reciprocal links and tiered link building.

Expired domains

An expired domain is one whose registration has lapsed and that someone else then registers again, and the links that already point at the domain come with it. Two of the nine pages list expired domains under the label. Game of Registrars, a study by Tobias Lauinger and co-authors presented at the USENIX Security Symposium in August 2017, measured how quickly that re-registration happens: "We find that 10 % of all com domains are re-registered on the same day as their old registration is deleted." The paper's introduction gives that figure as a share of deleted com domains, and its sample was every domain deleted from four popular zones during four weeks in 2016.

Links on sites that were taken over

None of the nine pages lists this under the label, and one study describes it. David Wang, Stefan Savage and Geoffrey Voelker followed a single network for nine months in a study presented at NDSS in 2013, and they report: "on December 1, 2011, we found 821 compromised sites in total". The count is of sites in that one network on that one date. The network used taken-over sites to place pages in search results, and its software added links from those sites to other sites in the same network; the 821 is a count of sites, not of links.

Negative SEO closes the list. SEOptimer alone among the nine pages lists it, and a 2015 paper by Theo Lynn, Malcolm Brady and Ieva Masevic defines negative SEO as a third party applying SEO techniques to lower a target site's ranking. To review the links that already point at your own site, see our guide to a link audit.

What we check on a placement

A label tells you little about a link. What you can check is the site the link sits on and the page the link points to, and that is what we check on every placement we deliver. The checks below are about the quality of the publisher and the accuracy of the placement.

Before a placement, we look at who owns and runs the site, its technical foundations, its standing in search, its authority and readership, its track record and its editorial quality. Indexed pages, organic traffic and its trend, Domain Authority, Domain Rating and referring domains are weighed together. We turn away sites whose metrics look impressive but whose traffic does not hold up. Some sites we turn away outright: sites that share hosting, registration, templates, analytics, boilerplate legal pages or author identities with other publishers that present themselves as independent; sites with faked traffic or metrics; resurrected expired domains; and sites with thin or spun content. We also check the HTTP status code that the client's target URL returns before a placement goes out, so no link is pointed at a dead page or a redirect chain.

After publication, we check that the page is live, that the link sits in the body copy, that the anchor and target URL match the order and that the page is indexable. Only then is the URL reported to the dashboard. If a link is removed, or its page is taken down, within 12 months, we replace it like for like under our 12-month replacement cover.

On a Rhino Rank Curated Links order, the link goes into an article that is already published. On a Guest Posts order, the article is written in-house by our UK team. The same checks apply to both. The full standard is set out on our quality assurance page.

Frequently asked questions

The counts in these answers are of the nine dated pages we read on 4 October 2026.

What is black hat link building?

Black hat link building is a label that guides put on link building done with certain techniques, and the nine dated pages we read for this guide list different techniques under it. Of the link techniques counted on this page, the pages list links in comment sections most often, then private blog networks, hidden links, and link farms or link wheels. Which techniques the label covers depends on the page: no link technique appears on more than five of the nine we read.

What are black hat backlinks?

Black hat backlinks is the name guides give to links built with the techniques they list under the black hat label, and the term is also written blackhat backlinks. SEOptimer's page of 23 April 2019 calls building black hat backlinks a common type of black hat SEO. Whether a given link counts as one depends on which guide's list you use.

What are examples of black hat link building techniques?

Across the nine dated pages we read, the examples counted on this page are links in comment sections, listed by five of the nine; private blog networks, hidden links, and link farms or link wheels, listed by four each; and link exchanges, expired domains and automated link-creation software, listed by two each. Tiered link building and negative SEO are each listed by one page, SEOptimer.

Is keyword stuffing a black hat link building technique?

Eight of the nine dated pages we read list keyword stuffing under the black hat label. Keyword stuffing is an on-page technique, not a link technique, and a page can stuff keywords without building a single link.

Who decides what counts as black hat?

Each page's author decides what counts as black hat on that page. There is no single list: of the nine dated pages we read, no link technique appears on more than five. The counts on this page are counts of nine dated pages read on 4 October 2026, not a measure of the market.