Research by security firm Symantec suggests that the raw value of a WoW account is now higher than a credit card and its associated verification data.

One card can be sold for up to $6 (£3) suggests Symantec, but a WoW account will be worth at least $10. An account that has several high level characters associated with it could be worth far more as the gold and rare items can be sold for real cash.
http://news.bbc.co.uk/2/hi/technology/6526851.stm

The value of virtual goods is increasing.