"We've done tons of user testing on this, and it turns out it doesn't work. Touch surfaces don't want to be vertical.
It gives great demo but after a short period of time, you start to fatigue and after an extended period of time, your arm wants to fall off. it doesn't work, it's ergonomically terrible.
Touch surfaces want to be horizontal, hence pads.
For a notebook, that's why we're perfected our multitouch trackpads over the years, because that's the best way we've found to get multitouch into a notebook.
We've also, in essence, put a trackpad -- a multitouch track pad on the mouse with our magic mouse. And we've recently come out with a pure play trackpad as well for our desktop users.
So this is how were going to use multitouch on our Mac products because this (he points at someone touch laptop screen) doesn't work."