Well the difference should be this:
-auction: whoever has the highest bid wins
-sale: you name a price and see if a buyer comes up
In these forums noone really cares, you usually just set a reserve and once it's met you sell to the higher bidder.
There's also a website for auctions run by the same people here; it's organised in a different way, there are categories, but i can't tell you if you will have more luck selling here or there, never tried the new site. I'm a traditionalist