This article entitled "Virtual Economy In U.S. Set To Make Billions" url http://www.huffingtonpost.com/2009/12/30/virtual-economy-in-us-set_n_407105.html claims that "Virtual goods such as weapons or digital bottles of champagne traded in the US could be worth up to $5 billion in the next five years".

Is there a correlation between the use of virtual goods and of virtual currency? What growth rate do you see in the use of virtual currency? Doubling every 5 years? or faster?