A flack at Zillow recently tried to interest me in the online real-estate startup's listings of celebrity homes. A fun topic, and one that might distract reporters from talk of the company's finances after a recent layoff. (Zillow is infamous in real-estate circles for its questionably accurate estimates of home prices.) I asked her: What about the celebrity home of Zillow CEO Rich Barton? The answer I got: Zillow only lists celebrity houses which are up for sale. But Barton has been happy to use his personal residence to generate publicity for the site before, blogging about the sale of his previous Seattle home. Why so shy now?A search of King County property records showed that since the June 2007 sale of his previous residence, Barton hasn't purchased property under his or his wife's name. Is he renting? Zillow's Amy Bohutinsky says Barton does own his own home, which a Seattle-based tech reporter says is in the city's Madison Park neighborhood. He may well have bought it under a trust. If so, it's the first time he's chosen to do so in years of owning Seattle-area real estate. It's telling that Barton, an ex-Microsoft executive who got rich through the software giant's spinoff of travel site Expedia, has suddenly become interested in keeping his home address private. Could it have anything to do with his new business of telling everybody what their neighbors' homes are worth?