I’m wary of drawing sharp distinctions between “active” and “passive” media. Are we really “passive” when we’re immersed in a great novel or a great movie or listening to a great piece of music? I don’t think so. I think we’re deeply engaged, and our intellect is extremely active.
But when we watch a great movie - we sat down to absorb Nashville last Friday night to celebrate a new couch - you do assume a kind of passivity. You sit back and allow Robert Altman to take you somewhere for a couple of hours. Your mind is active but your fundamental posture is passive. That's different than sitting down at your computer and looking at a monitor, as you work or surf. Which is why web-TV seems to me problematic beyond 3 minutes or so. Now, web-TV can be turned into passive watching, by downloading onto a TV screen or watching a video podcast on the stairmaster. But I think they are different animals as experiences.