Zynga's filing comes at a time when many large Web companies are looking to tap the public markets. LinkedIn, which went public in May, saw shares more than double on its first day of trading. While shares fell in the days following the IPO, LinkedIn has rebounded and is now trading at around $94 -- more than double its offer price. Pandora ( P), which debuted last month on the public markets, is trading at around $20, above its offer price of $16. Daily deals company Grouponfiled for a $750 million IPO last month, while near-term offerings from Facebook and LivingSocial are also expected. "While I'm humbled by the size of the audience we enable to play today, we're just getting started," wrote Pincus. "Let's play." --Written by Olivia Oran in New York. >To follow the writer on Twitter, go to http://twitter.com/Ozoran. >To submit a news tip, send an email to: email@example.com.