Twitch is back at it again on Copyright issues. It apparently replaced music from Metallica on Blizzard's gaming channel without telling users, while keeping it Blizzard's YouTube and own Twitch channels, as in Electronic Frontier Foundation's "hall of shame" report here.
Twitch created a furor with a lot of music takedowns last fall, without giving apparent rights for counternotice (Verge story), after massive input of takedowns for old clips. We've covered the quirks in the DMCA takedown law before, and the platform does not have to let you appeal.
I've wondered a little bit about "original music" which these days, is often melodically related to music written before in a manner that remains obscure. (There is amazing similarity between an organ Toccata by Percy Fletcher and an early Schumann piano toccata.) Some composers say that all "composing" includes some copying (like Shostakovich copying Bruckner). I wonder if this could become a problem down the road.