Editor's Note: TheStreet ratings do not represent the views of TheStreet's staff or its contributors. Ratings are established by computer based on metrics for performance (which includes growth, stock performance, efficiency and valuation) and risk (volatility and solvency). Companies with poor cash flow or high debt levels tend to earn lower ratings in our model. NEW YORK ( TheStreet) -- Zillow (Nasdaq: Z) is trading at unusually high volume Friday with 1.9 million shares changing hands. It is currently at 2.9 times its average daily volume and trading down $1.54 (-2.6%) at $56.30 as of 4 p.m. ET.