Primarily a Dutch Auction is an auction that works in reverse.
In a normal auction, bidders would offer a higher and higher price for the goods until only one person remained, that one being the one that offers the highest price for the goods.
In Dutch Auction, the goods DECREASE in price until some one steps in to purchase the goods at that price. The interest arises when the item WILL sell at some point, but if you wait too long someone may come in and purchase the goods before you and you'll miss out.
TIP
Set your purchase price that you are prepared to pay first, and place your bid at that price. Don't wait, as the item may be sold before you have chance to place a bid.