There's going to be (and already is) a fair amount of attention payed to this critique by Freddie DeBoer of the liberal blogs as excluding the left from "serious" discussion. My sense is that whatever the truth of the complaint, it's less about blogs than it is about American politics in general.
But at any rate, it gives rise to a good set of Sunday Questions. Conservatives: are there any policy options, in any area, which are simply not discussed by mainstream politicians because they are perceived as out of the mainstream to the right? What are they?