aspect ratio of most new tft monitors. they are not 16:9.
if you watch a 16:9 movie on a 16:10 monitor, black bars will appear on bottom and top. but most of the new movies are not even 16:9 anymore, they are 2,35:1, thats super widescreen and gives even bigger black bars on your screen.
hey look at my cool new 16:9 widescreen!
thats 16:10 man. 16:9 screens are fucking rare.