SpuriousLogic brings us this excerpt from a BBC report:
"Prof. Heeks said very accurate figures for the size of the gold farming sector were hard to come by, but his work suggested that in 2008 it employs 400,000 people who earn an average of $145 (£77) per month creating a global market worth about $500m. ... Already, he said, gold farming was comparable in size to India's outsourcing industry. 'The Indian software employment figure probably crossed the 400,000 mark in 2004 and is now closer to 900,000,' said Prof Heeks. 'Nonetheless, the two are still comparable in employment size, yet not at all in terms of profile.' Prof Heeks suspects gold-farming might be an early example of the 'virtual offshoring' likely to become more prevalent as people spend more time working and playing in cyberspace. "
We discussed the life of a gold farmer