Hi, it's David G from Zillow.com, first let me just say, OUCH!

As traffic metrics go, comscore's way off - I just pulled up omniture - Zillow had 5,1 million uniques in March '08.

Thanks for the critique. Redfin's actually not a competitor, they're a brokerage who publish Zestimates on their site and have in fact advertised on Zillow.

Local CPM ads actually work really well for real estate pro's who want their phones to ring (something you can't do with CPC) but many of the ads on Zillow are CPC with some CPA. Zillow's a high-tech media business. The same folks who develop Zestimate algorithms are building ad targeting systems that can target cable ads for example to movers and lawnmower ads to people with large lawns.

As to Zillow's prospects - expect Zillow to change online mortgage shopping (launching very soon) and expect to see for sale listings on the site continue to grow now that brokerages are uploading listings in bulk to the site.