I don't believe it's the hits.
They say it's SALES, and I believe it. There is no incentive for them to lie and count hits instead of sales.
"This list, updated hourly, contains top-selling items that are currently available for purchase."
http://www.amazon.com/exec/obidos/tg/new-for-you/top-sellers/-/books/all/ref=b_tn_bh_be/104-1774827-1270358
I think you know it as well, you just want to generate some traffic and publicize the books you mention. This is not very imaginative.
For ex---this applies to the Times---my agent has had a book sell 90,000 and not get on, and one sell 25,000 and get on. Now, some of that is competitor sales at the time . . . but much of it has to do with which stores they take their data from.