Real estate data provider Zillow (Z) reported that second-quarter net income shrunk 19% to $1.3 million, or 5 cents a share, after reporting a profit of $1.6 million, or 0 cents per share, in the year-ago period.

Analysts estimated a loss of a penny per share, according to Zack’s Investment Research.

The falling second-quarter profits were largely a result of a 116% expansion of sales and marketing costs to $12.2 million from $5.6 million a year earlier.

Revenue at the company, on the other hand, reached record levels in the quarter as usage across mobile and web spiked, with more homes viewed on a mobile device than on a desktop. Zillow revenue ballooned 75% to $27.8 million from $15.8 million in the second quarter of 2011.

The Seattle-based company tipped to mobile in the beginning of the year. More homes are now viewed via Zillow on a mobile device than on a desktop each month. In July, 168 million homes were viewed on Zillow Mobile, or 63 homes per second.

"We continue to extend our leadership and expand our three core marketplaces in real estate, mortgages and rentals with products and services that delight consumers and help local professionals better manage and market their businesses,” said Spencer Rascoff, chief executive officer of Zillow.

Average monthly unique users grew 61% to 33.5 million in the second quarter compared to 20.8 million unique visits for the same period in 2011. The company said July had record traffic with more than 37 million unique visits to its mobile applications and websites, up 59% from a year earlier.

In July, Zillow announced that it expanded its exclusive partnership with Yahoo (YHOO) to include rentals. In June, the company acquired RentJuice, which provides rental relationship management software for landlords, property managers and rental brokers.

Zillow expects third quarter revenue to arrive at about $30 million. That represents a near-60% growth from the $19.1 million the company earned in the third quarter of 2011.