I agree that the karma points derived from article posting is essentially a lot of nonsense. I remember once finding an article on slashdot in the middle of the night about java being rumored to be open sourced before it actually happened. I quickly posted it to reddit since I had not already seen the article there, and within the next day I obtained about 80 karma points from posting that one article. The news article would have ended up on reddit regardless of if I posted it, but because I was lucky enough to see the article first among reddit readers, I got a lot of karma points.

I doubt that anyone has ever gotten 80 karma points from writing a single comment, but it is difficult to use comments alone as a ranking system since there are a lot of people who just read articles and will ignore any additional commentary.