Can you play Quake Live on linux or mac?

Unfortunately, as of 17/12/2013 this is no longer possible. Quake Live is Windows only.

Yes you can! Just visit the Quake Live website and follow the on screen instructions!

As tested with timedemos on dualboot machines it is actually proven that the Linux version is faster than the Windows version!

So if you are using Apple MacOS or GNU/Linux, visit the site and join in on the fragging mayhem!