Silent auction
The biggest second hand online marketplace in Finland did a big update to their service recently. In addition to overhauling their whole user interface they also added a few new features.
One of the biggest changes was the ability to take offers for the items you are selling. As a buyer you can make an offer and the seller has 24 hours to wither accept or reject the offer. It's a bit like an auction but not really. As a buyer you can't see what others have offered so there is no way telling whether your offer will be valid or not.