Running Macbook with Display Closed

I was observing the design of a macbook and when the screen is closed it looks like the rear vents rea open to allow heat to flow out the back of the computer. It also looks as though the screen closes off the top part of the vent where heat normally flows out when the display is open, forcing the heat to go out the back. Now, I haven't done it yet, but has anyone run their macbooks with their displays closed and not harmed their computers in any way? I'd assume it shouldn't because it's right in the manual that you can run the computer with the display closed.

Thanks

no it wont hurt it. either way.

I do it all the time, for hours or even days at a time. The Macbook vents perfectly out the back.

Good luck!

Thanks, thats what I figured.