The basic system works on three currencies: gold, gems, and karma. The karma currency is not trade-able, and is only used for unique in-game rewards. However, the gold and gems currencies can be traded freely; with gems being purchasable with real money, and are the only accepted currency in the item-store. This works similar to EVE Online‘s PLEX system, but goes a bit further.
With EVE‘s system, PLEX can only be used for one thing: to add game-time to your account. Players can purchase extra PLEX, and sell it in-game to players, who can then purchase it with in-game credits. This gives players a way to play EVE Online free, if they’re good at making money in-game.
Guild Wars 2 system is similar, but instead of one purchasable item, it gives players an entire item-store to buy things with. This also creates a dynamic between the two currencies, as gold will always fluctuate in value, while gems will not. The reason being, that the price of items in the item-store are a lot more consistent than items sold in-game by other players.
This system then creates a sub-market that will actually allow players to make, potentially, huge profits by constantly trading gold for gems. When the value of gold is high, trade it all for gems. As the value drops, trade your gems back to gold, and depending on the fluctuation, you’ll get more gold back then what you started with.
The good news is that the item-store will only sell cosmetic items and items to speed up certain in-game processes; most likely EXP boosts and things of that nature. ArenaNet made the following statement about selling items that give players any sort of advantage,
But it’s never OK for players to buy a game and not be able to enjoy what they paid for without additional purchases, and it’s never OK for players who spend money to have an unfair advantage over players who spend time
The reasoning behind this move is to prevent gold farmers from ruining the game as they’ve done with other MMORPGs. By allowing the players themselves to buy and sell gold, it destroys the RMT blackmarket.
As far as I’m concerned, ArenaNet can do no wrong. The system sounds great, and I’m even more excited for GW2; if that’s even possible.