NPD's track game subs: Please don't get it wrong!

GamesIndustry.biz reports that NPD is going to track subscription data around games.

This addresses a long-unaddressed market demand for data around online games. Many have asked if the PC game business is as unhealthy as retail game sales indicates, or whether the market is in fact just changing. (Whether all of PC gaming's revenues are being sucked into a giant WoW crater and whether that is healthy for the ecosystem or not is another matter entirely).

I applaud NPD's efforts, but I do worry that they are going to mess it up. A couple of things that make this space complicated to cover:

• Game service subscriptions vs individual game subscriptions. e.g. GameTap vs World of Warcraft.
• Revenue from non-subscription sources. e.g. Advertising, In-game item sales, etc.
• Where the consumers are located. e.g. US consumers subscribing to/playing Korean games and vice versa.
• Hardcore vs Casual. I'm sure they'll cover World of Warcraft. Will they cover Pogo? Likely. Will they cover casual game subscriptions on MSN Messenger? Less likely. Club Penguin?
• Platforms. Does an Xbox Live subscription count? Is that game revenue or platform revenue?

According to their press release, they are polling "thousands of gamers ages 13 and older who are members of NPD’s online panel of 3 million consumers", which seems like a prescription to messing up a couple of the areas above (e.g. just missed most of Club Penguin's user base, most of the casual audience, etc)

Anyhow. Steps in the right direction, but still I worry.