Virtual Currency Draining Real Economy?

A recent report on Marketplace suggests that the time spent gaming online and doing ‘virtual purchasing’ may be draining money out of the coffers of the government because such activity is not taxed. Edward Castronova, a professor from Indiana University posits that the amount of real currency exchanged for virtual items is in the region of US$100 million per year, and that the amount of commerce taking place online, as he states it "You give me gold pieces, I give you magic armor, that sort of thing," is between 2 and 20 billion US dollars. Castronova is the author of a book called Synthetic Worlds.
For example, IGE is a site where you can buy 2 million gil for only US$37.99. But according to a gamer interviewed in the Marketplace report, "IGE is like the scum of the world." True online gamers resent the dabblers who purchase high-level items without working for them. This brings up a somewhat disturbing idea: the gaming sweatshop, where uneducated teens or others are forced to play games online and perform repetitive tasks for hours to build virtual items that can then be sold online for actual currency.
Is the online gaming world getting out of hand? Should there be legislation regulating online activity? Should online purchases in virtual worlds be taxable? Or will the maturation of online culture eliminate this sort of behavior?