I'm a bit perplexed that eBay has auctions that have a fixed time ending, and so winners are often determined by who can 'snipe' the auction, by putting in the winning bid at the last possible microsecond.
Often specialised software is used to achieve this.
An alternative system, like New Zealand's Trade Me auction site uses, is that the auction is auto-extended by two minutes, if a bid is put within the last two minutes of the auction.
What this means in practise (from what I've seen in auctions I've particpated in) is that an auction might be extended by 10-30 minutes due to 'last minute' bids between two or more bidders.
Now, it should be noted that the auto-extending dynamic doesn't completely negate the sniping dynamic. For example if Bob sees that Alice has put a bid on a item for \$1000, which is due to close in two days, and Bob is willing to spend \$2000 on that item, it still makes sense for Bob to hold off bidding on the auction until closing time. Alice may not be paying attention\be at her computer (though trade me allows auto-bids) at closing time, and by bidding at the last minute, he reduces the window in which she can outbid him.
This auto-extending system seems like it evaluates the market value more genuinely than the sniping system.
Ebay is surely aware of this dynamic, and it must be a conscious decision to keep the sniping-allowed system.
My hypothesis is that systems that allow sniping encourage higher selling prices, as bidders pre-emptively increase their bids as to stay out of the sniper's willing-to-bid range.