Amazon is best known as a sprawling online marketplace where almost anything can be bought and sold, and where almost anyone — including far-right groups — can try and make money.
The company has faced criticism for its bookstore's recommendation system, which has promoted titles that share vaccine disinformation and conspiracy theories, as well as allowing white supremacist publishers to directly sell on the site.
But Amazon also offers another way to make money: an affiliate program that lets websites point potential shoppers to Amazon-listed products and earn referral fees if those shoppers buy anything.
Websites listing current bestsellers, for instance, might provide Amazon-affiliate-tagged links to those books in the company's bookstore.
The ABC found several websites based in the United States and Australia that share hateful material targeting immigrants and trans people, as well as climate change and election disinformation, also promoting links to the Amazon bookstore that appeared to use the company's affiliate program tag.
The ABC is choosing not to name the sites to avoid amplifying their content.
The books promoted by the websites covered a variety of topics, including a so-called "exposé" of climate science, a discussion of political nihilism and an adventure book about manhood.
Claire Atkin, co-founder of the advertising watchdog Check My Ads Institute, said for a company of Amazon's size, "it's not just about the ads".
"When these websites tap into Amazon … they're getting legitimacy by being an Amazon affiliate," she said.
The websites examined by the ABC all shared links to Amazon that included an individualised affiliate tag, although it is unclear if the website owners still held active accounts. Likewise, there is no definitive way to know how much these sites may have earned.
Amazon declined to comment on the status of the websites identified by the ABC, or whether it would investigate.
Its own policies exclude websites from the affiliate program that "contain materials or activity that is hateful … or discriminatory (including on the basis of race, colour, sex, religion, nationality, disability, sexual orientation, or age)".
"Amazon does not endorse the content or views of any individuals or companies that are part of the Associates Program," a spokesperson said.
"We remove any associates who violate our guidelines."
A home for a white supremacist publisher
Sometimes hateful content ends up in Amazon's own shop front.
In 2020, ProPublica exposed how Amazon's self-publishing service was being exploited by white supremacist authors, and American researchers recently identified a white nationalist publisher selling almost 24 of its titles in Amazon's book marketplace, as well as in other online bookstores.
"It’s the biggest, it’s very accessible, it’s very easy to use," Elise Thomas, senior OSINT (open-source intelligence) analyst with the Institute for Strategic Dialogue, said of Amazon's appeal to such groups.
"And evidently [the publishers] are able to do it for a significant period of time without being taken down."
The Southern Poverty Law Center (SPLC) found publishing company Antelope Hill — linked to the National Justice Party — boasted about having a book about the differences between Jewish and white people trend number one in Amazon new releases under the subcategory of "Jewish social studies".
"They are definitely using Amazon to gain visibility for their books," said Michael Edison Hayden, a senior investigative reporter with the SPLC.
The question is not whether such books should be banned, Hayden added, but how Amazon may be used to fundraise for entities that promote hatred towards minorities.
"And the question of whether a huge tech giant, which some people argue has a monopoly on the book industry, is helping to provide money to this particular group," he said.
According to the SPLC, Amazon removed some of the titles identified by the researchers — one book, for example, that reportedly blamed Jewish people for the existence of transgender people — but left others.
"In other words, Amazon has declined to take into account the fact that they are financially abetting a white supremacist group," they wrote in a report about Antelope Hill, published in August.
An Amazon spokesperson said the company has content guidelines and would "promptly investigate any book when a concern is raised".
"We remove books that do not adhere to those guidelines," he said.
Scrutiny on big tech's ad platforms
While a minnow compared to Google and Facebook's vast advertising ecosystem, Amazon also offers brands a range of ways to promote their products on and off Amazon's own site.
Ms Atkin of Check My Ads said companies like Amazon should be far more transparent in how they managed their advertising technology, as well as affiliate programs — including by maintaining a list of sellers removed for violating their terms of service.
So far, there has been no public systematic review of Amazon's ad ecosystem and where its ads appear.
But the ABC found, for example, ads for Amazon books and products served by Amazon's own ad technology on The Daily Caller — a right-wing American website that has in the past published white supremacist authors.
Amazon declined to comment on its relationships with specific ad publishers.
Beyond the opportunity to make money, being part of Amazon's extended ecosystem — selling on their website, displaying their ads or being an affiliate — arguably provides websites and publishers with a degree of legitimacy thanks to an association with one of the world's best-known brands.
"Amazon has a lot of power to decide whether that should or shouldn't be," Hayden said.