Having only had HDTV in the house for roughly 48 hours, I've already found something interesting to note. While watching "the game" last night (the second in a series I won't talk about until we have some good news) I was amused by the little tricks that the designers use while serving screen elements that'll work with both normal television and HDTV screen widths. Sounds sort of familiar, doesn't it?
When FOX needed to show an informational banner across the bottom of the screen (see figure), the sides would fade out in a gradient while watching in HD. My guess (and I didn't check) is that normal TV viewers don't see the gradient at all, rather the banner just flows across the entire screen. The gradient edges are probably there -- but only appear if you have a widescreen HDTV.
The parallels here to web design are obvious: that steps are taken to ensure a usable experience, regardless of screen size. Now aren't the television designers lucky to have just two, predictable widths to deal with?
I'm also beginning to notice other design choices that reflect the growing number of HDTV customers. Many commericals are presented in 16:9 format, and some add colored bars on top and bottom that seem to purposely mesh visually with the black bars on left and right that appear when a square image is shown on a widescreen.
Having to support two viewport sizes must be challenging -- but like the web, designers are finding creative ways to make both experiences work.