There is a fascinating meta-price market emerging at Ebay, according to this WSJ article. The online auctioneer is taking the natural step of selling, in volume, its sale prices. For example, it is tracking and selling price trends in everything from Sony DVD players to Ford Explorers. All sorts of people are using the data, from Intuit (tracking electronics price declines to estimate the value of charitable gifts) to the PGA (who are tracking the used-golf-club market). As has become standard wrongheaded practice, of course, the people most directly affected by this sort of thing — like Kelley’s Blue Book, the main arbiter of user-car prices — are myopically saying this will have no effect on them. They’re wrong.