From Jay Hancock's Blog:
I can't reproduce the Zillow graph, apparently because it's a flash chart. But it says my house is worth $491,000, which is about $5,000 more than we paid for it in late 2003. I know Zillow values aren't gospel, but they're a rough and interesting indicator of where house values have been and are going. We paid $485,000 for the Howard County house in November 2003. According to Zillow it was worth $670,000 by 2006, and as recently as last summer it was worth $540,000, according to the Web site.