Of the "Big 4" proposed "web 2.0" IPOs - Facebook, Zynga, Twitter, and Groupon* - only the former 2 are showing the potential of big gains in profits at this time. Not that it will necessarily matter when they come public in a country starving for high growth stories. While I like Zynga the company, Zynga the proposed valuation is already troubling. Riding the back of Farmville, ...