Many real estate websites such as Realtor.com and Zillow.com are utilizing user friendly online methods for property owners to get an estimated market value for their homes. In a general and limited format, these complex logarithms will supply a reasonable valuation. The margin of error is quite high, however, as the probability of over-homogenization and anomoly deviations can substantially affect an estimate. Experienced real estate brokers utilize an appraisal-like method called a comparative market analysis to specifically define and value tangible and intangible differences and upgrades. It is this hands-on, subjective approach that is necessary to arrive at a true market value. The moral of the story is this: Always consult an experienced real estate broker before pricing your home!