Game streaming platform Twitch has updated its rules to ban the streaming of titles rated Adults Only by the ESRB.
The move has likely been prompted by the imminent launch of controversial shooter Hatred, only the second game ever to recieve an AO rating for its violent content and themes.
Hatred lets you play as a mass-murdering sociopath on a "genocide crusade" to kill as many civilians as possible. Its marketing has made much of the game's extreme violence and has successfully used it to cause controversy and generate attention.
ESRB ratings only apply in the US, although copies of AO-rated games in all regions are affected.
Few developers submit games to the ESRB expecting an AO rating due to the reluctance of retailers to stock games branded with it. In a calculated move, Hatred made headlines when it gained the the rating - which only helped raise its profile further.
In contrast, previous AO-recipients Grand Theft Auto: San Andreas and Fahrenheit: Indigo Prophecy were edited and resubmitted so they could pass with a lower "Mature" label instead.
These versions are fine to stream, Twitch has clarified. Games rated 18+ by other ratings boards - such as Europe's PEGI scheme - are also fine.
The ESRB website lists just 26 games rated AO. Almost all were slapped with the rating due to being adult-themed titles with "strong sexual content".
Of the list, only the examples listed above and Manhunt 2 will likely be familiar.
That list will soon grow with the upcoming addition of Hatred - due to launch on 1st June.
Twitch's blog post does not mention Hatred by name, but mentions that its change has been prompted by "emerging issues in the video game industry".
"Our goal at Twitch is to create a safe, welcoming, inclusive community platform where everyone can feel comfortable and have fun. From time to time, we update our Rules of Conduct (RoC) in pursuit of this goal and to match emerging issues in the video game industry.
"Previously, we made game-specific decisions about which games would and would not be available for broadcast - sometimes due to overtly sexual content, sometimes due to gratuitous violence. This is unsustainable and unclear, generating only further confusion among Twitch broadcasters. We would like to make this policy as transparent as possible.
"Today, we're updating the RoC with regard to Adult Only (AO) games. Simply put, AO games are not welcome on Twitch. Please refer to the ESRB's Ratings Guide and list of Adults Only games for more information.
"The RoC is a living document that we update regularly based on community feedback and industry developments. We would appreciate your feedback, too."