South Park Accurately Sums up Freemium Games - (Freemium isn't Free)

^ "fortunately"

There has been talk before of taxing in-game currencies. Worse yet, i think some countries already do.

http://www.irs.gov/pub/irs-drop/n-14-21.pdf

Fortunately, that's talking about bitcoin, namecoin, and the like. However, it wouldn't take much to expand it into the videogame territory.