Terra Nova posted an interview with a price-fixer in WoW. The guy scans the auction house for items he thinks are being bought by bots. He then turns the tables on the bots by artifically inflating the price of the goods in question and outwitting the bots.
The way it works is like this: There are bots that rely on tools like Auctioneer to ascertain bargain prices of goods. Players log in with an accout and run the bot software and go take a nap, alt-tab to porn, whatever. The bot account scans the auctions and compares prices against its own database of prices, and if it finds "bargains" it will buy them.
According to Alex Tabony in the Terra Nova interview, he artifically inflated the price of a given item by buying it up for several days and relisting it at a much higher price. At some point the bot database is going to see that firefin snappers, which have been selling for 75 silver are now being listed for 10 gold -- all by Tabony, but the bot doesn't know that, muhahah. That becomes the new price for firefin snapper in the bot's database.
At this point Tabony would start to list firefin snapper for five gold each at the auction house. Players won't buy them because they know that is far too much to pay for a firefin snapper -- it's a smelly dead fish after all -- but the bot will see the five gold price as a bargain. By the lice-ridden beard of Thrall, the bot will say, this firefin snapper is selling at half price! So the bot will snap up the firefin snappers at the five gold price and then Tabony does an Irish jig as he revels in his virtual wealth and the knowledge that he is smarter than a bot!
Kids, be careful before you try this at home, especially if you're not an egghead. You might get stuck with a truckload of happy fun rocks.