According to Lindan Lab CEO Philip Rosedale, all Second Life transactions, from trading to buying/selling, total the equivalent of $1.3 million in US currency exchanged daily—or an average of $US6.50 per user per day. To scale this even more with the Kotakulator: if WoW implemented a cash-based economy at the same spending average, their transactions would total $US58.5 million per day. Second Life money might not be real money, but a lot of users have bought into it.
And all I can say is, that's a lot of cash to spend on pixel penises.
Second Life merchants estimated to rake-in over $1.3 million total every day [videogamesblogger]