The Economist reviews a paper which examines the impact of bestseller lists on book sales. The results are intuitive, so I won't go into them here.
I think the far more interesting paper to do would be to examine how bestseller lists are gamed: it's fairly well-known in the publishing world that places on bestseller lists can be bought and sold, just like countries defend their exchange rates. How? By buying up books from the few stores from which the lists are calculated.