A few years ago I decided to do some Microsoft exams and get some certification to help switch jobs. As part of that process I obtained a few video training courses, most notably those from CBT, to help me revise and fill in those blanks resulting from things I didn't use day to day. Several of those courses still used, or at least refered to, class based addressing. So do a number of fairly recent texts I've seen from people/organisations that should know better.
The point I'm trying to make here is that, whether we like it or not, this stuff is still being taught, so we are going to continue seeing those questions.
As an aside, serverfault.com/questions/12854/cidr-for-dummiesserverfault.com/questions/12854/cidr-for-dummies is a great example of a question that got shoved onto SU when it should have been put out of its misery.
