What is a common characteristic of a traditional auction format?

A traditional auction format is characterized by the method in which bidders engage and indicate their interest in participating. In this setting, bidders typically raise their hands to signal their desire to place a bid. This physical gesture allows the auctioneer to easily recognize active participants and track who is willing to move the bidding forward.

The other options do not align with the conventional behavior seen in traditional auctions. Placing bids electronically is a feature of modern online auctions rather than traditional in-person auctions. The notion that all items are sold without a starting bid is not generally accurate, as many auctions begin with a set opening bid. Similarly, while some auctions may require deposits, this is not universally applicable to all traditional auctions, where bidders may simply raise their hands to participate without financial prerequisites. Therefore, the act of raising hands to indicate interest is indeed a hallmark of the traditional auction environment.