Yep Raph Koster was featured on GU Comics today because of that comment.
http://gucomics.com/archives/view.php?cdate=20060215
Of course he explains it on his website and apparantly he has a very different defination of what a single player game actually is. By his definition single player games are indeed doomed if they even existed in the first place.
http://www.raphkoster.com/2006/02/10...-games-doomed/
I can't say I exactly aggre with him but he does make many good points in his essay and in his replies to the comments that followed.