No actually you guys are wrong about some things..
While it is true that what they are talking about in that article is not "HDTV" but rather just really high resolutions, nvidia cards and drivers do in fact support HDTV output.
Have any of you guys connected nvidia cards to HDTVs? I've done so a lot, using component, DVI, and HDMI cables.
Nvidia can output all HDTV signals. If you connect via component cables the nvidia drivers will automatically switch to HDTV mode and you will get a bunch of options most of you have probably never seen before. One of these options allows you to select what kind of HDTV signal you want to output - you can select all HDTV signals, including 720p and 1080i.
If you use a DVI or HDMI cable you can also choose to output 1080p. Also, when using DVI or HDMI cable, you may need to tell your video card it is connected to an HDTV and not a monitor. You can go into custom timings and check the box that says "treat as HDTV"
Using this method you can send HDTV 720p and 1080p signals to your PC monitor, though it may not be able to read the signals correctly. However, some monitors, like the Dell 2405FPW can actually read both 720p and 1080p correctly and can even scale them to 16:9 correctly if you choose aspect in the monitor's image settings (the monitor can't do that if you simply make a 1280x720 or 1920x1080 custom resolution).
I've taken a screenshot to show you guys what it looks like: