CityVille and FarmVille developer Zynga's growth finally slowed down during its June quarter, the company revealed Thursday.Ahead of an estimated $1B initial public offering (which is being delayed due to "rocky stock markets" ), the company revealed its financial performance for the quarter in an SEC filing, showing that its year-on-year profits declined around 95 percent, from $27.2M to $1.3M.The company's revenues continued to grow, though at a slower pace: the $279.1M it generated in its quarter ending June 30 was 15 percent higher than the $242.9M it saw in its March quarter. By comparison, March revenues were up 24 percent from those in the previous quarter.One important metric for Zynga is its "bookings," the term used to define revenues from both microtransactions and ads if measured immediately at the time of sale before any adjustments -- such as the 30 percent Facebook Credits take -- are made. This is, in a sense, the company's measurement of virtual goods sales.Bookings for the quarter were down for the first time in company history. The $274.7M it reported is a 4 percent drop from the $286.6M in the prior quarter.That 4 percent drop could easily be explained by a decline daily active users during the period: quarter-to-quarter, DAUs dropped from 62M to 59M, or roughly 4 percent, due to a more competitive market than in prior quarters.Zynga attributes its profit decline to two major factors: the company did not launch any new games in the first half of 2011 until Empires and Allies on March 31, and the company spent more than it traditionally had on hiring, acquisitions, and its international growth.Its transition to the Facebook Credits system also hurt profits, the company said.As part of today's filings, the company said that recently-conducted third-party analysis puts the probability of its IPO at 75 percent, down from 80.However, that same analysis increased the company's valuation, from $13.98B to $14.05B.