Wondering why Apple chose to add a camera to the iPod nano, but not the revised iPod touch? You're not alone, but one Mr. Steven P. Jobs has an answer for you: it's because the touch is a game machine, you see. Seriously -- that's what El Steve told the inimitable David Pogue today after the Rock and Roll event. According to Steve, Apple wasn't "exactly sure how to market the touch" at first, but once they listened to their cust