Summary Box: ‘Farmville’ maker gets cold shoulder

THE DIP: Zynga Inc. saw its stock dinged on its first day of trading Friday ? an unexpected turn of events for a closely watched initial public offering seen as a precursor to Facebook’s next year. The stock fell 50 cents, or 5 percent, to close at $9.50.

WHAT A SURPRISE: Eye-popping jumps have been the trend this year for freshly public Internet darlings such as LinkedIn Corp., which saw its stock double on its first trading day.

PREDICTIONS FOR FACEBOOK: One thing is clear: A hot IPO is not guaranteed.