Seattle online real estate site Zillow says it had nearly 32 million unique visitors in January, more than double the count from a year ago.

In a regulatory filing, Zillow said it ended January with 31.7 million unique users. Twelve months ago, the site had 15.7 million users, marking a 102 percent increase.

Zillow is in a tight race for clicks with a host of online websites, such as realtor.com and trulia.com. Zillow had 7 percent of the search traffic in the U.S. in December, according to Experian Hitwise. Zillow was No. 2, behind Yahoo Real Estate.

In January, Zillow added a neighborhood feature that the Seattle-based real estate site says will let buyers and renters learn about neighborhoods from their Facebook friends.

Zillow went public last July.