A study conducted by The Appraisal Institute shows that the popular house valuation website, Zillow.com, overestimated the value for 40% of the properties by more than 10%, and only 0.88% of the property prices were underestimated by 10% or more. The study suggests that homeowners’ estimates of value may be more accurate than Zillow’s estimates. Click here to read the full study, published in the Winter 2010 Appraisal Journal.