"Yeah, why? Your typical modern Mac comes with all the Unixy goodness you could ever need, right? But there are a bunch of Linux PPC distributions that you can, if you feel the need, install on your Apple hardware.
"In my efforts to answer the big 'Why?' question, I contacted Kai Staats, cofounder and CEO of TerraSoft Solutions. I asked him questions he's been asked a thousand times before about why anyone should install Linux on their Mac. I'm sure the last thing he wanted to do was go over the same old ground with some ignorant journalist. But he did anyway..."