Attire

The protocol for each type of auction -- on-line or in-person -- varies in several significant ways. For one thing, someone attending an in-person auction must be dressed, as in, wearing clothes of a respectable sort. On the contrary, someone attending an on-line auction could be wearing their bathrobe, pajamas, or even (heaven forbid) just their birthday suit!

Advantage: On-line auctions.

Viewing

Perhaps the biggest challenge facing the on-line auction is the fact that it’s not very easy to see the goods for sale. Unlike an in-person auction where you can walk around a room looking and touching everything up for sale, an on-line auction requires you to trust in WYSIWYG, or What You See Is What You Get. You have to trust that the person selling the item pictured will actually send you the thing shown on your screen. But still, you have no way of viewing the piece in 3D. You can’t gauge its size, dimensions, weight, or other physical characteristics as easily as if you were holding it in your own two hands.
Advantage: In-person auctions.

Global reach

On-line auctions open up your pocketbook to the world, giving you global buying power. The World Wide Web connects you with buyers and sellers across the world so you are no longer limited by geographic proximity. For example, if you want to sell your family heirlooms, you don’t need to restrict yourself to the people down the street...you can sell to someone in Germany, Italy, Australia, or even Zimbabwe. Plus, more available buyers may mean a higher price for your antique.
Advantage: On-line auctions.

Sound

Some on-line auctions are integrated with live sound so you can hear the auctioneer’s rattle and calls of bidders. However, technology and bandwidth are not up to speed enough yet to make this a truly live event. Usually, a delay of a few seconds (depending on your modem speed) adds a bit of a time-warp effect. This can make it challenging to keep up with the pace of bidding. Some auction houses recommend turning off sound so you aren’t left behind.
Advantage: In-person auctions.

Trust

With an in-person auction, you can usually meet the person who once owned the item, as well as the auctioneer in charge of selling it. This gives you the opportunity to determine how the piece was cared for, and how trustworthy the people are pricing it. An on-line auction, on the other hand, doesn’t let you meet anyone face to face. You can’t look into their eyes, feel the firmness of their handshake, or follow them home if you’re unhappy with your purchase. You just have to trust that their on-line identity is reality. In other words, you trust that they’re not about to enter a witness protection program!
Advantage: In-person auctions.

Prices

Even prices are affected by the type of auction. In some cases, an on-line auction may experience inflated prices...going beyond what the normal market might bear had the auction been held in a traditional setting. Usually misinformed buyers encourage running up the price, causing things to get a little out of hand. Then again, the same bidding fever and competitive nature is exhibited in-person as well. When one collector knows another one really wants a specific piece, and that collector doesn’t really want that person to have it, he or she may run up the price to make the buyer pay more as a form of punishment.
Advantage: Depends.

Bidding

Another way the two types of auctions differ is in how you place a bid. At an in-person auction, a quick nod of your head easily ups the bid. At most, you have to wave your hand to signal your interest in the item. Then at the end of the day, you’ll need to "settle up" by filling out the appropriate paperwork. Buying something from an on-line auction takes just a click of the mouse to bid on an item. A couple of clicks and keystrokes later, and you’ve charged it to your credit card and had it shipped to your home. No need for social interaction, so it’s a perfect way to participate for shy, introverted individuals.
Advantage: On-line auctions.