Are virtual rewards a trap?

Games can be won or lost, they can be challenging, they can be social, they can (or even should) be entertaining. But in most cases games don't pay you. There are exceptions in the case of gambling or professional sports, but in the huge majority of cases people didn't play for profit. But then came persistent online games with their virtual rewards, titles, and achievements, and suddenly it seems for more and more people those virtual rewards have become more important than playing the game or

World of Warkraft...