that site is a joke, it doesn't even get into the differences of HDTV resolutions such as 720p, 768p, 980i, 1080i, 1080p and so on and so forth.
It's more like an HDTV promo site without dwelling into too much information.
for example: Widescreen: see 16:9 (Aspect ratio of widescreen DTV formats for all HDTV and some SDTV (Standard Definition) content) DUH! it's wrong! 16:9 is the encoding aspect ratio. The content can be 4:3, 2.35:1, 1.78:1, 1.66:1, 2.2:1, 2:1 or any aspect ratio.
Don't go to that website unless you want to be misled.