This reminds me of Wikipedia deletionism, as if either Wikipedia or Stack Overflow will run out of space and they'll have to move into a new building if they don't clear out these topics. Why not just keep them and keep getting the Google ranking and free advertising?
Joel recently tweeted something to the extent "You think you should have the right to ask anything. The fact that we don't allow that is why your happy when SO shows up in your google search."
I do not think that is a valid argument. If I gave you a house a hundred times the size of your current house, and then dumped the equivalent of ninety house contents of junk in it, would you be happy?
(Almost) every bit of knowledge that is on StackOverflow can be found elsewhere on the net, too. People go there not because it has knowledge, but because of its density.
