Zillow (NASDAQ:Z) celebrates its IPO on the NASDAQ Stock Market on Wednesday, July 20, 2011. (Courtesy of Zillow.com)

Zillow.com hit Wall Street with a bang today, opening at nearly triple its $20 IPO price and closing at $35 per share. The surprising pop gives the online real estate company a valuation of more than $1 billion, 35 times the company's 2010 revenue.

The company, which has never made a profit, kept a tight lid on the number of shares it offered, selling 3.46 million shares of its Class A common stock to raise $71 million. Zillow also has the opportunity to sell an additional 519,000 shares to its underwriters. If it does, it will mean Zillow is only selling 13 percent of its total share count.

A similar strategy has been popular with other tech companies that have gone public in recent months, designed to drive up investor demand by limiting the number of available shares, reports the Wall Street Journal.

Zillow's IPO debut was not affected by the weak housing market, though in its prospectus the company warned that any drop housing sales or increase in mortgage interest rates could have a negative effect on its business.

Zillow CEO Spencer Rascoff with Co-founders Rich Barton and Lloyd Frink. (Courtesy of Zillow.com)

The growing company -- it's the No. 3 real estate site in the U.S. according to data from Experian Hitwise -- is not yet profitable. However, the gap is quickly narrowing due to rising revenue: Zillow’s net losses for Q1 in 2011 were $826,000, down from net losses of $2.8 million during the same quarter in 2010. The company reported a net loss of $6.8 million in 2010, compared to a net loss of $12.9 million in 2009.

Zillow makes its money from subscription fees from real estate agents, as well as from selling advertising to agents, mortgage companies and other real estate companies. The site, which has a database of more than 100 million homes, is free to use for its reported 22 million unique visitors.

The company said it expects to use the proceeds from its IPO as working capital and for sales and marketing purposes.

Z is for Zillow: Zillow employees celebrate the online real estate company's IPO. (Courteesy of Zillow.com)