Ask HN: What's your biggest gripe with craigslist and/or ebay?
From a usability, content or technology standpoint.
Imagine an auctioneer in real life implements this policy. "Going once for x. Going twice...." They begin mouthing the word "sold" when a competing bidder jumps in at x+1. The auctioneer proceeds as though nothing happened ("Sold!") except that the sniper wins ("For x+1...").
So that really has nothing to do with coding, but those are my gripes with each.