Reddit, Something Awful and 4chan all have quite a bit of slivers of pure poetry within them. This forum was meant to be something different; and I think that's what pg is thinking about when he said that.
This site will still have plenty of good discussion, just like those places, but the amount of bad discussion/trolling/useless information will be increasing
Even if we can't count on the honor system, we can still count on occasional slivers of pure poetry. That's something.