Fewer paying players on FarmVille

Paul Sakuma/AP/Press Association Images

Zynga lost money and received less revenue than anticipated in the second quarter because CityVille, FarmVille and other games are not attracting as many paying players as they should.

Its stock tanked in after-hours trading and dragged down Facebook's shares as well because the social networking icon relies on Zynga for a good chunk of its revenue - 12% last year. The news comes as Facebook prepares to report quarterly earnings on Thursday, its first as a public company.