Zillow has landed $30 million in new financing, which comes on top of the $57 million already raised. The new round values the 155-employee “Zestimate” provider at $350 million, according to reporting by Rebecca Buckman at The Wall Street Journal.

CFO Spencer Rascoff called to provide some color to a fairly complete profile I wrote after the Inman conference in August. He reiterated blog comments that while it seems counterintuitive given the collapsed housing market, the site’s traffic is up 17 percent year over year since last August, according to internal records, with 4.4 million unique visitors. That contrasts with overall online real estate use, which is down 2 percent.

With the market down, “it’s less fun to Zillow yourself and your neighbors and friends,” Rascoff concedes. But “we’re getting less voyeuristic traffic and more buyer and seller traffic.” Using Zillow gives buyers and sellers “an edge.”

Rascoff adds that advertising is really coming into play. The site currently has 20 national ad salespeople, and typical national advertisers include mortgage lenders, auto makers, home improvement, home developers and insurance. “It’s an easy sell” given the site’s affluent base of users, he says, which has an average household income of $90,000.

Of 300 media sites that have more than 3 million uniques, he notes that Zillow is No. 1. Of the sites that have more than 1 million uniques, Zillow is No. 8.

While national advertisers are increasingly drawn to Zillow, Rascoff actually has greater long-term expectations for the EZ Ads product, which have attracted 6,000 advertisers with an average spend of $50. This fall, he expects to see a rash of new advertisers on EZ Ads, ranging from mortgage brokers to local politicians. The largely local-based ads make up 10 percent to 20 percent of total revenues now but have the potential to dominate Zillow’s advertising, he says.

Rascoff also discussed the rising spam issue, as aggressive and increasingly desperate Realtors and mortgage brokers abuse the system — a problem that is affecting the entire real estate industry. (My wife, a Realtor with Century 21, is getting dozens of Realtor-related spam e-mails a day.)

Zillow is aggressive trying to route out the spam, with 12 staffers flagging everything on the discussion boards and the Wiki, says Rascoff. The problem area, though, is the site’s real estate guide. But he seeks to keep the spam issue in perspective. One in every thousand contributions is a spam.

Rascoff also clarified what makes up a Zillow “contribution,” since there have been some questions in the industry that the site’s 25,000 daily contributions is as meaningful as it seems. He says everything that is sent is literally called a contribution; every photo, every e-mail. Of the 20,000 to 25,000 contributions, 10,000 are photos.