Look suspicious, where is the Apple Logo on the back of the screen
 

I just noticed that there isn't an Apple logo on the back of the screen. Is it possible that they have a video camera on the back side that feeds into the desktop?

This would explain how this is done.

It would be unlikely that Apple would throw away the logo on the powerbook.

thx
RLC

Look a little closer. Two clips on the top of the lid.
 

On the top of the lid, there appears to be two clips. I bet those clips are mounted to the video camera on the backside of the powerbook.

Mystery solved.

thx
RLC

Perhaps, but given the desktop shows the menu bar, I bet they set their desktop wallpaper to green or blue, then used the blue screen to impose the image of that desktop minus the laptop over it.

That's exactly what they did. You can still see some hints unkeyed green at the corners.

Since the camera doesn't move, all you have to do is shoot a short clip of the scene without the PowerBook, then shoot the scene with the PowerBook with a bright green desktop image and replace the green with the video of the scene without the PowerBook. Final Cut Pro or After Effects can do it easily.