Zynga (ZNGA -9.2%) ended an ugly day trading 20% below its IPO price. Aside from Playdom's (DIS)...

|About: Zynga (ZNGA)|By:, SA News Editor

Zynga (ZNGA -9.2%) ended an ugly day trading 20% below its IPO price. Aside from Playdom's (DIS) unveiling of Marvel: Avengers Alliance for Facebook, there wasn't any noteworthy news to move shares. But bearish opinions are easy to find: Dave Thier argues Zynga's problem is that rising customer expectations force it to develop more expensive games to generate the same amount of revenue, all while competition grows.