i think its just the size of the pixel . . .
obviously, if you have a 17" monitor and 19" with both resolutions of 1280x1024, the 19" will have larger, since it has the same amount of pixels, but more area to cover
so, its coincides with the resolution and size of the monitor . . . i like HIGH resolutions
. . . thats why we're waiting for a 1900x1080 hdtv . . . none of this 1024x768 crap . . .
hehe, i was so bored one day, that i just counted my pixels to make sure that they were correct . . . yep . . . 1400x1050 . . .