Official, game-sponsored exchanges for real-money trades (RMTs) are more than places where players can swap goods for money. Fundamentally, these exchanges act as an honest broker between two extremely different types of player: cash-rich/time-poor players (people with jobs, for the most part) and time-rich/cash-poor players (retirees and young people). Seen through this lens, a "game" is just a bunch of applied psychology that makes kids work long hours to earn virtual gewgaws that adults are trained to desire. In this "Free to play, pay for stuff" world, kids are alienated from the product of their leisure by a marketplace where the game-company skims a piece off of every transaction.Developers still finding that it pays to get in the game
The psychology of this is fascinating, since it all only works to the extent that the game remains "fun". One key element is that skilled players (eg kids) must not feel like the rich players are able to buy their way into positions of power. Game devs are advised to sell defensive items - shields, armour, dodging spells, but not offensive ones. A skilled player will still be able to clobber a heavily armoured rich player, given enough time (and skilled players have nothing but time, by definition), but may quit in disgust at the thought that some rich wanker is able to equip himself with a mega-powerful sword or blaster that gives him ultimate killing power. No one wants to play in a game where one player has an "I win" button.
For me, the most fascinating thing about this is how it can be seen as the application of the business model that downloaders have been advocating since Napster: "Don't sue the kids who download your music or movies, rather, see them as the marketing that sells the same media to cash-rich adults who lack the time to use P2P software."