Online brokerage Redfin is expanding into New York. Westchester, Long Island, and Queens are all available, although Manhattan and Brooklyn still remain beyond its reach. In California, the site now covers Sacramento and the Central Valley. Other existing markets include Boston, Chicago, Washington DC, Baltimore, the San Francisco Bay Area, and of course Redfin’s home base of Seattle.

At the same time, the company announced it is adding up to 200 additional data fields for Realtors to use. Depending on the area, Redfin will now list property details such as price history, the sellers’ mortgage history, cumulative days on the market, lot square footage, and will display addresses on a map.

Redfin says that traffic grew 300 percent last year to 1.6 million unique visitors. ComScore is more cautious, estimating only 324,000 U.S. visitors in March, 2009.