A research arm of the World Bank has produced a comprehensive report on the size of the grey-market virtual world economy in developing countries -- gold farming, power-levelling, object making and so on -- and arrived at a staggering $3 billion turnover in 2009. They go on to recommend that poor countries be provided with network access and computers so this economy can be built up -- a slightly weird idea, given how hostile most game companies are to this sort of thing.
Kind of staggering (even if one has to wonder how they came up with that figure) – plus they’re talking about 2009, and I don’t see the market having decreased over the last year and a bit.