As has been reported in numerous places the new Macs has an HDCP enabled display port. This means that if you want to watch a DRM protected movie on a separate display that display must have HDCP enabled.
Everyone grab your linux!
It appears as if everyone thinks that they need to go start using that linux they’ve heard so much about. Well guess what, the movies that won’t play on a separate display (non-HDCP) on your Mac (windows too btw) ALSO won’t play on a linux box period. That’s because videos that use DRM (ie itunes rentals etc) don’t have support under linux anyway.
Don’t get linux
Let me save everyone some time that thinks they need to start on the linux band wagon because because Apple is HDCP compliant. Don’t switch to Linux. If your only reason to switch to linux is because of this HDCP thing then you are in for a world of hurt. Linux is a pain in the ass to setup and if you don’t know enough to buy DRM free formats then when it comes time for you to do anything on your linux box you’re going to be SOL and have absolutely no clue how to use your computer.
As for windows users
It seems that every windows user that has commented on this issue said something to the effect of “Ha! I HATE MACS anywayz!1 I keep my windows!!” guess what, you guys have had HDCP control enabled ever since Vista came out. You were worse off than OS X BEFORE OS X.
The bottom line
Don’t buy stuff with DRM, you don’t need it. Think of it this way, if you buy something with DRM you are only renting it. If it has DRM you do not own it.