Findings from the Vuze study noted in this article should be taken with a grain of salt. Pro-BitTorrent conclusions support Vuze's business model.

That said, the article poses an unanswered question I think I can shed a little light on:

What it doesn't reveal, at least not explicitly, is why those users buy DVDs but not the downloadable movies sold or rented by authorized outlets such as CinemaNow, iTunes or Amazon.com.

The answer: Handbrake. Pop a DVD into the computer, adjust the settings/formats, and let it rip.

If the industry really doesn't understand why savvy content consumers avoid "approved" files, they're worse off than I thought.