I'm guessing he's not geeky enough to join an SW board as well.
(Not that that says much about me, either.)"It's because the image is meant to be stretched horizontally to the correct aspect ratio on widescreen displays"
Correct. Unfortunately, the impression that is being given is that, in order to "unsqueeze" the picture for a 16x9 display, it must first be "squeezed", and this is not the case. The picture is simply made taller (simplification!) to begin with (i.e produced with an incorrect aspect ratio), so that if one could widen the picture, it would have the correct aspect ratio and have higher resolution to boot. If one cannot widen the picture, then the extra resolution is removed instead.
"Squeeze" is a terrible misnomer to use to describe "anamorphic" DVDs.
I'm really tired of DVDs now.
(j/k)
[EDIT]
"then the extra resolution is removed instead." Yes, I am quoting myself. This makes me think of Joe Kane's proposal to add a second stream of video information to be added to the regular 720x480 information (yes, zion, I know about pixel sizes - I just think we've opened more than enough cans of worms here.) This would have the benefit of having an SD quality stream for existing DVD players, and the ability to bump up to an HD quality stream for newer players which would combine the added resolution. This idea, of course, did not come to pass. Blue-Ray and HD-DVD will be bringing us HD material instead.