I've been using computers since the days of tape drives. Personally, I've tried to use a touch screen on occassions only to find it's a regular computer screen.

I think there needs to be some recognised international symbol that touchscreens could show to indicate they can and should be touched - pointer icon (index finder extended hand symbol) with emanating circles appears to be the de facto standard. They do rather lack affordance.

I've never yet tried to pinch zoom a magazine cover or whatever though.

Reminds me of the Star Trek movie scene when Scotty picks up the mouse and talks in to it.