I actually think that there are a lot of topics regularly discussed at RPGnet that, perhaps, some people here would benefit from and/or can add to constructively (e.g, discussions of basic genre tenets, theoretical models of play, the definition of subjective hobby jargon, etc). I'm all in favor of discussing fairly important topics like this wherever the people are in a position to learn from and/or contribute to them constructively (including EN World, The Forge, Dragonsfoot, etc).
What I'm not in favor of, however, are some of the 'Screw those folks at Alternate Site X for thinking differently than us!' threads that crop up from time to time... kind of like this one did. Productive discussion is good, regardless of where it comes from - what wastes space are threads like this one where somebody gets their panties in a bunch over what goes on at another message board and decides to vent about it here. What does that do, but tie up board resources with a petty personal complaint?
I'd rather see more RPG-related topics spill over from elsewhere on the internet, than more self-serving, close-minded, calls for action against Forum X, Y, or Z spill over from elsewhere on the internet. I mean, really - at least RPG-related discussion that spills over from other forums has the potential to be productive, but attacks leveled at other online communities? Not so much.