Joseph Goodman of Goodman Games has weighed in on the topic of how well the current edition of Dungeons & Dragons is doing from his perspective. He offers some very interesting data, which, if accurate, suggests that things aren't as gloomy for third party publishers as Clark Peterson suggested in his recent post on the same subject.
I have no horse in this race myself, since, as I've repeatedly said, 4e holds even less interest for me than 3e. Nevertheless, it's interesting to see someone step up and attempt to put things into a historical context. I'm not sure what to make of it all, but it's good that there's open discussion of this topic, as I find it all very fascinating.