"Simply put, Adult Only games are not welcome on Twitch."
Update: Twitch has clarified the whole "versions of these games in all territories" statement made in the initial release, as well as how games with multiple ratings will work via the following amendment:
If a game's US version is rated Adults Only by the ESRB, you should not broadcast that game on Twitch. However, ESRB rated Mature versions of Adults Only titles are permitted for streaming, such as Mature versions of Grand Theft Auto: San Andreas and Fahrenheit: Indigo Prophecy.
Games rated 18+ by other rating systems are fine to stream, so long as they are not rated AO by the ESRB, and they don't violate the standard language of our RoC and ToS.
While this seems pretty clear-cut, Twitch does cause a bit of confusing by stating "our policy extends to versions of these games in all territories. Generally, if the US version is rated for Adults Only (18+) or has an equivalent rating in your territory, you should not broadcast that game on Twitch." The problem here being that in territories such as Australia, ratings discrepancies begin to appear. For instance, Hotline Miami 2 received the "refused classification" label in Australia (arguably the equivalent of an "AO" rating) for its intense adult content, whereas in the US, it simply received an "M" rating.
Does this mean that no-one can stream the game? Or just Australians? What if you're an American living in Australia?
For reference, here is the official ESRB list of "Adults Only" games in the US, and thus, the list of games now banned from being streamed on Twitch. Noteable examples include Manhunt 2 and Grand Theft Auto: San Andreas.
"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," said Twitch, explaining the change.
How do you feel about this change? Personally, I think Twitch streamers who specifically state that their channel contains adult content should be allowed to stream whatever damn game they please.