From Jewel Quest to World of Warcraft, gaming has always occupied a niche online. By combining the social might of Facebook with the narrative element of experiential games like Oregon Trail or The Sims, Zynga — a social network game developer based in San Francisco — was able to become one of the fastest-growing companies on the Internet. Millions of Facebook users play FarmVille, Mafia Wars and the company’s other titles — with many shelling out real dollars to add to their virtual barnyards or crime syndicates. A recent New York Times report put Zynga’s estimated value at billion, noting that investments have quintupled its worth over the last two years. Andrew Trader was a member of Zynga’s founding team in 2007, and until last year served as executive vice president of sales and business development. Previously, Trader was CEO of Tribe.net, a social network sold to Cisco in 2007, and co-founded Coremetrics, a website marketing analytics firm.…