Reddit has long been the most permissive of the major social media sites. Whereas Facebook tries to ensure that all content on the site is suitable for a general audience, Reddit willingly hosts content that is sexually explicit, violent, or disturbing in a variety of other ways.

But even Reddit has its limits. On Wednesday, the site announced a new policy clarifying its rules against content that incites violence. "We will take action against any content that encourages, glorifies, incites, or calls for violence or physical harm against an individual or a group of people," Reddit administrator landoflobsters wrote. Promoting harm to animals is also against the rules.

Within minutes, moderators started to ban a long list of controversial subreddits, including /r/Nazi, /r/DylannRoofInnocent, /r/SexWithDogs, /r/WhitesAreCriminals, and /r/PicsOfDeadKids.

The bounds of propriety remain fairly wide at Reddit, however. Commenters pointed out that /r/WatchPeopleDie—which is exactly what it sounds like—is still around. Landoflobsters said that site administrators have "no plans to remove it for now." The self-explanatory—and horrifying—/r/CuteFemaleCorpses is also still active.

Evidently, merely depicting violence is fine as long as people in a subreddit don't glorify violence. In practice, of course, the line between these things is pretty thin. A subreddit devoted to merely discussing violent acts is naturally going to attract people who like to promote violent acts—especially after bans of related subreddits where those people previously hung out. Reddit's new policy seems like the basis for an endless game of Whac-A-Mole as the Internet's creeps search for new places to exchange disturbing content.

Still, as we wrote last month , there's some evidence that Reddit's past crackdowns reduced the amount of toxic behavior on the site. Research that looked at a 2015 crackdown that banned a number of subreddits found that "regular users of these subreddits toned down their language as they moved to other areas on the site." So while the new policy won't eliminate offensive content from Reddit altogether, it still might nudge the site's culture in a more wholesome direction.

Disclosure: Ars and Reddit are owned by the same parent company, Advance Publications.