Online real estate marketplace Zillow (Z) reported record first-quarter net income of $1.7 million, or 6 cents a share, on strong mobile and website traffic.

Earnings improved from a loss of $826,000, or a loss of 6 cents a share, in the year-ago period.

Zillow also said it would buy RentJuice, a San Francisco-based company that provides rental relationship management software for landlords, property managers and rental brokers, for $40 million in cash. RentJuice launched in 2009 and employs 31 people. The company offers a subscription-based suite of marketing and productivity tools.

The firm said revenue hit a record $22.8 million, up 103% year-over-year, marking the sixth consecutive quarter of over 100% year-over-year revenue growth.

"Mobile usage and site traffic grew substantially during the first quarter, which led to record revenue and EBITDA levels exceeding our prior outlook, and our sixth consecutive quarter of triple-digit, year-over-year revenue growth," said Spencer Rascoff, chief executive officer of Zillow.

Average monthly unique users grew 84% to 31.8 million in the first quarter of 2012 compared to 17.3 million average monthly unique users for the same period in 2011. 

For the first time, more homes are now viewed via Zillow on a mobile device than on the Web, the company said. In March 2012, 155 million homes were viewed on Zillow Mobile, or 57 homes per second. In the year-ago period, 44 million homes were viewed on Zillow Mobile or 16 homes per second.

Premier Agent subscribers totaled 18,616 at March 31, up 74% from the year-ago quarter. Premier Agent revenue is reported as part of marketplace revenue. Marketplace revenue increased 141% to $16.6 million from $6.9 million in the first quarter of 2011.