Late last year, Peter Gutmann, a researcher from New Zealand, published a pretty scathing article, entitled A Cost Analysis of Windows Vista Content Protection. One of his conclusions is that "Overall, Vista's content-protection functionality seems like an astonishingly short-sighted piece of engineering, concentrating entirely on content protection with no consideration given to the enormous repercussions of the measures employed".
Microsoft has now responded in an article on the Vista Team Blog site, entitled Windows Vista Content Protection - Twenty Questions (and Answers). Written by Dave Marsh of Microsoft, this article aims "to address some of the other points raised in the paper". While Marsh's piece does try to attach Guttman's comment, it confirms other points. For example, MS acknowledges that DRM increases CPU usage by stating"the use of additional CPU cycles is inevitable".
Also inevitable is the reaction to Marsh's piece - one comment on the Vista blog suggests "This essay has essentially CONFIRMED every horrible charge leveled at Vista by Gutmann".