Zillow's S-1 registration statement and five subsequent amended filings have shed considerable light on the company's business model and plans. The filings show that since its inception in December 2004 the company has run up a cumulative deficit of $79.5 million through March 31. But Zillow looks to be headed toward profitability, having trimmed net losses from $21.2 million in 2008 to $12.8 million in 2009 and $6.8 million in 2010. During the first three quarter of 2011, Zillow's losses totaled $826,000, as revenue more than doubled from a year ago to $11.26 million.