Zynga’s first day of trading on the stock market closed below its offering price.

The social games developer, known best for Facebook games Farmville and Mafia Wars, has been the poster child for what many have heralded as the social games revolution.

At the company’s San Francisco headquarters, Zynga founder Mark Pincus rang the opening bell and made a “raise the roof” gesture.

“We brought the Nasdaq here,” said Pincus. “With our IPO, we’re accelerating this mission of connecting the world through games. It’s just getting bigger.”

Zynga set its share price at US$10. Shares initially rose to $11, but soon fell and closed at $9.50.

“Zynga’s weak performance reflects the broader market for IPOs,” writes The New York Times. “Newly public technology stocks have been buffeted by macroeconomic turmoil and jittery investors, who are skeptical about the business models.”

Following the poor day on Wall Street, Zynga’s chief operating officer John Schappert said, “We’re not looking at it today or tomorrow, or what we could have squeezed out. We’re looking at the long run.”

Zynga remains one of the most profitable social gaming developers, reporting earnings of $30.7 million on revenue of $828.9 million for the first nine months of 2011, reports The Times. However, user growth has slowed recently while marketing costs remain high – $122 million over the same period. A further concern is that Zynga appears unable to separate itself from Facebook, in spite of recent efforts to launch its own social gaming platform.