NEW YORK (AP) — An anonymous online forum called 8chanhas drawn attention in the wake of mass shootings in Texas and Ohio because violent U.S. extremists have used it to share tips and encourage one another. The site suffered sporadic outages Monday after its cybersecurity provider cut off support for what it called a “cesspool of hate.”

What is 8chan?

The online message board dates back to 2013. It allows users to post graphic and extremist content and doesn’t censor posts.

The site has been linked to violent extremists. Police are investigating commentary posted on 8chan believed to have been written by the suspect in a shooting Saturday that killed 22 people in El Paso, Texas.

If there is a connection, it would be the third known instance of a shooter posting to the site before going on a rampage. In March, the gunman in mass shootings at two New Zealand mosques posted a rambling manifesto to the site, as did another who injured several people and killed one at a California synagogue in April.

Why did 8chan go down?

The site went down briefly after security provider Cloudflare said it would stop supporting the site. Without Cloudflare, the site was vulnerable to outside hackers who shut down the site.

“8chan has repeatedly proven itself to be a cesspool of hate,” Cloudflare CEO Matthew Prince wrote. “They have proven themselves to be lawless and that lawlessness has caused multiple tragic deaths.”

Can 8chan be regulated?

8chan’s popularity rose after the similarly named but unaffiliated site 4chan cracked down on more extreme posts. Because the U.S. doesn’t specifically outlaw domestic terrorism the way it does foreign-sponsored extremism, such sites enjoy broad protection from government oversight under the U.S. Constitution’s First Amendment.

Even if that weren’t the case, sites like 8chan are also difficult to regulate because users can simply move on if moderations grow more strict or if a site shuts down.

“Dealing with incitement to violence and hatred online goes well beyond any one platform,” the American Defamation League’s Oren Segal said.