I think it'd be cool if you could set a max bid that could not be seen by anyone (always with the ability to increase it) .. I'm participating in this preview auction but am afraid someone will wait until the last minute of the auction and outbid the top bidder.
If I were allowed to bid my maximum amount and have the bidding system bid for me the next amount up when someone else bids I wouldn't have to be home and no one could jump in at the last few minutes and bid knowning what the current amount to win is.
I think a few other auction companies on the internet do it this way.