David Friedman (yes, that David Friedman) posted a course outline for a World of Warcraft-center course in economics with some interesting insights,
There is no antitrust law in WoW, which makes it a good place to observe collusive behavior by sellers. My wife, who spends more time in the auction house buying ad selling than I do, has observed both an attempt to corner a market and an attempt, at least partly successful, to form a cartel—a cartel she was invited to join. Her refusal was met by a threat to drive her out of the market by underselling her. The organizer of the cartel had apparently not read Aaron Director’s analysis, reflected in McGee’s classic article on the myth of predatory pricing; it had not occurred to him that if he was selling, at an artificially low price, ten times as many gems as the interloper, he was also losing money ten times as fast. It took only a few days for him to discover the flaw in the strategy and abandon it.
The comments have some good discussion of the oddities of pricing in the Auction House (such as the completely bass-ackward fact that in WoW — unlike the real world — raw materials tend to trade for more than the cost of many finished goods, which can actually help infer the monetary players attach to skill point increases).
Maybe someday Blizzard will release a huge anonymized dataset of Auction House transactions for folks to play with.