Zillow (NASDAQ:Z) reportedly guides on its Q4 call for Q1 revenue of $36M-$37M and 2013 revenue of $165M-$170M, above Street estimates of $34M and $160M. In spite of strong revenue growth, EBITDA margin is expected to stay flat, thanks partly to an expected 70% increase in sales/marketing spend. Q4 Markeplace revenue +95% Y/Y to $26.8M (+99% in Q3), ad revenue +22% to $7.5M (+15% in Q3). Z +5.2% AH in response to the guidance and a Q4 beat - shares rose 7.8% in regular trading following rival Trulia's Q4 report (I, II).