O.K. - pop quiz: which social media game boasts an active fan-base of roughly 31 million players every day? Heres a hint: its a happy place where you can plant virtual crops that can be harvested, or ask your neighbor to chase away raccoons. If you guessed Farmville, then youre correct! Earlier this week, we began an advertising pilot with Zynga, the folks who brought you Farmville. For a short time,