Cloudflare said it had terminated the website as a customer and called the forum a “cesspool of hate”.
The website has repeatedly been used by suspects in mass shootings to spread their “manifestos” and reasons for carrying out such attacks, and has often hosted far-right messaging and imagery due to its known stance of being neutral about moderating content posted to it.
In a blog post in the wake of the two shootings in El Paso, Texas and Dayton, Ohio, Cloudflare chief executive Matthew Prince said the company could no longer offer web-based support and cybersecurity protection to the site.
Mr Prince claimed the suspect in the El Paso attack had posted to 8chan before commencing the attack.
“8chan has repeatedly proven itself to be a cesspool of hate,” he said.
“They have proven themselves to be lawless and that lawlessness has caused multiple tragic deaths.
“Even if 8chan may not have violated the letter of the law in refusing to moderate their hate-filled community, they have created an environment that revels in violating its spirit.”
Mr Prince added that the website had previously been used by the suspects in the attacks in Christchurch, New Zealand, in March and on a synagogue in California in April.
“In pursuit of our goal of helping build a better internet, we’ve considered it important to provide our security services broadly to make sure as many users as possible are secure, and thereby making cyberattacks less attractive — regardless of the content of those websites,” Mr Prince said.
“Many of our customers run platforms of their own on top of our network. If our policies are more conservative than theirs, it effectively undercuts their ability to run their services and set their own policies.
“We reluctantly tolerate content that we find reprehensible but we draw the line at platforms that have demonstrated they directly inspire tragic events and are lawless by design. 8chan has crossed that line. It will therefore no longer be allowed to use our services.”
8chan was created in 2013 as an alternative to the 4chan forum which had become popular with gamers. It was launched in response to perceived increased moderation on 4chan and promised less intervention or removal of content.
Removal of Cloudflare’s services leaves 8chan open to cyberattacks designed to disable the platform.
There are already reports on social media that the website has been taken offline.
However, Mr Prince said his company’s actions were unlikely to permanently keep 8chan offline – pointing to a previous incident where the firm cut off far-right website The Daily Stormer, only for it to reappear online using “a Cloudflare competitor”.
“I have little doubt we’ll see the same happen with 8chan. While removing 8chan from our network takes heat off of us, it does nothing to address why hateful sites fester online,” Mr Prince said.
“It does nothing to address why mass shootings occur. It does nothing to address why portions of the population feel so disenchanted they turn to hate. In taking this action, we’ve solved our own problem, but we haven’t solved the internet’s.”