HDN is High Definition News. Every single frame in it is HDTV, all right, but this time that's the problem.
I can't remember who it was, but some newscaster who'd moved from CBS to ABC once complained about how visual the latter network was. "If you said, 'that's water under the bridge,'" he reported, "you'd better have a picture of a bridge with water flowing under it."
TV news concentrates on stories that have pictures. Satellite-gathered news ignores stories on the north sides of mountains (in the northern hemisphere) on account of being unable to see the satellite from there.
Voom's HDN carries only stories shot in HD. So, on a day recently when stories like the war in Iraq, the U.S. presidential election and the conflict in Haiti were dominating other news sources, HDN's top story was that non-Chinese businesses, like McDonald's, were showing up in New York's Chinatown. Methinks it took up about half the newscast. The weather reports for Africa and Central Asia took up another good chunk (the maps were gloriously HD sharp). No Iraq. No Haiti. No election.
HDN is definitely HD. It just ain't particularly news.
Then there's the story of another recent HD-related start-up, USDTV. The home page of its Web site says, "USDTV is simply the most affordable way to view HDTV."
I'll sort of buy that (in a linguistic sense; I'm pretty tapped out otherwise). To watch HDTV, you need an off-air receiver, an HD cable box or an HD satellite box. Time Warner Cable charges zilch extra for its HD cable boxes, but its monthly fee for service that includes HD ain't lower than USDTV's $19.95, and the other cable ops charge even more.
Voom goes for twice as much per month as USDTV (now that it's charging), and the other satellite folks can't beat them either. And USDTV charges just $99.95 for it's off-air HD receiver-installed; methinks not even the computer-card folks charge that little. So I'll sort of buy their cheapness argument-for a few more months anyhow. 
On July 1, the beginning of the digital "tuner" mandate kicks in. That's supposed to mean that, when you buy an HDTV display, you get an off-air digital receiver included free. Free is cheaper than $99.99. And free offers exactly the same amount of HD as USDTV's $19.95 a month. But there's more.
USDTV says its total first-year cost is $339.35-equipment and service. That compares favorably on its Web site with what they say Comcast ($699.48), DirecTV ($866.88) and DISH ($769.80) would charge. They don't figure on stuff like Gateway's free receiver offers, but methinks they might still be cheaper.
But the monthly service (aside from helping to subsidize the cost of the receiver) delivers zero HDTV. All the HD that USDTV "carries" is the HD that's already available for free from broadcasters. This is listed by USDTV as "All local HD channels, plus HDTV for all the best programs & big TV events on the broadcast networks."
I like that "plus." It's not just broadcast HDTV but also broadcast network HDTV shows. Uh-huh.
Anyhow, methinks you might be able to buy an off-air HD receiver (definitely at least a computer card) for less than $339.35. And you get exactly the same amount of HD.
The really scary thing is that USDTV might actually be preventing viewers from getting all the HDTV they otherwise would. It all has to do with what you do get for the $19.95 a month -- 10 standard-def cable-ish channels: Discovery, Disney, ESPN and other stuff like that there. USDTV gets local broadcasters to carry those channels as conditional-access multicasts.
In USDTV's first market, Salt Lake City, the local UPN affiliate, KJZZ, carries four of those cable-ish channels, including both ESPN and ESPN2. That means USDTV has contracted for a big chunk of data rate on KJZZ. That means KJZZ can't carry HDTV programming, which UPN started to offer last season. So maybe you don't really get "all" the best programs on the broadcast networks. Or maybe USDTV doesn't consider UPN's HD offerings to be in the "best" category.