"The simple Apple logo against a plain backdrop provides a clean advertisement for Apple. Removing the logo removes the distinctiveness of the computer when it is turned off."

It still took them a while to put them on the right way up. The first few laptops they sold with the Apple logo on the lid, they were oriented so they were "right way up" for the user when the lid was closed. That made them all upside down in all those tech conference shots from the stage...