I wonder what makes HN so addictive. I have no facebook, no twitter no reddit. And no youtube during work. But damn, I can't miss all those goodies on HN!
The same effect, novelty which presents at random is highly addictive, creating compulsive behaviour of constant checking. (Guilty over here too)
I think being an information junkie is more of the reason of HN addiction.
If you're a human being in the normal (+- 3 standard deviations) bands of brain functionality, you're an information junkie, but people have different information diets/highs.