Here's a cool paper, for those who really enjoy the nitty-gritty of eBay bidding:

CiteSeerX — The effects of proxy bidding and minimum bid increments within eBay auctions

It talks about the effect of sniping as a strategy for winning auctions and why sniping makes sense to do over incremental bidding. Interestingly, there is a bit of an inefficiency in eBay's system introduced by the fact that there are minimum "increments" allowed at different stages of the auction, and these increments mean that it isn't always the best to be the very last sniper to enter a price. Instead, these guys think that the best strategy is to be the FIRST of the snipers who enters a price, because that person gets a slight advantage when other bidders' bids are rejected as not exceeding the minimum increment.

Anyway, I know some people here could care less about this stuff, but for those who enjoy a little dash of theory, this paper is a cool read.