Nevermind that housing is in the doldrums and has been since 2007. Seattle-based Zillow (Z), a real estate website with listings and sales data on more than 100 million U.S. homes, soared Wednesday in its first day of public trading on the NASDAQ, closing at $35.77, up  nearly 79% from its initial offering price of $20 a share. The share price gives Zillow, which has yet to turn a profit since its 2004 inception, a market valuation of more than $623 million based on 17.4 million shares outstanding. At one point, in morning trading, the stock surged as much as 200% to $60 per share. Zillow originally priced its 3.46 million-share IPO at $12 to $14, then raised it to $16 to $18 a share, before settling on $20. The company has seen remarkable growth in revenue and users in recent years. In May, 22 million unique users visited Zillow’s website and mobile applications, representing year-over-year growth of 102%, the company said in regulatory filings. Zillow generates revenue from local real estate professionals, primarily on an individual subscription basis, and from mortgage professionals and advertisers. During the three months ended March 31, it had revenue of $11.3 million, up 111% from $5.3 million in the comparable period a year ago, according to SEC filings. For the years ended December 31, 2008, 2009 and 2010, it generated revenue of $10.6 million, $17.5 million and $30.5 million, representing year-over-year growth of 49%, 65% and 74%, respectively. The company narrowed its net loss to $826,000 for the first quarter of 2011, from a loss of $2.8 million in the year-ago quarter. As of March 31, it had an accumulated deficit of $79.5 million, according to regulatory filings. This year has been good for IPOs, as hungry investors snap up Internet stocks. Social networking site, LinkedIn Corp. (LNKD), saw its shares more than double in its public trading debut in May. LinkedIn’s shares closed at $94.25 at the end of its first day of trading, more than 109% above its $45 IPO price. IPO proceeds in the United States surpassed $10 billion for the third consecutive quarter, signaling the ongoing strength and attractiveness of the IPO market as an avenue to raise capital, according to US IPO Watch — an analysis of IPOs on U.S. stock exchanges by PricewaterhouseCoopers. IPO proceeds in the second quarter reached $11.9 billion compared to $5.2 billion in the second quarter of 2010 — a 129% increase in total proceeds raised. The same period also witnessed increased in IPO volume — 47 IPOs compared to 41 in the second quarter of 2010 and 32 in the first quarter of 2011. Year to date, as of the June 29 report, 79 pricings generated $24.3 billion in proceeds, more than double the amount raised for the first half of 2010, when 70 IPOs generated $9.4 billion. Write to Kerry Curry. Follow her on Twitter @communicatorKLC.