When I was searching for a house I used 5 or so apps to do so. I found that Zillow had many, many listings that were very old, but were placed up top and the dates changed to make it look like it was just listed. However, checking the actual data for that listing shows that it was not pulled from the market and relisted, it was just Zillow constantly boosting really crappy houses that had been on the site for a long time.<p>In short, trust none of them, use multiple services, and keep looking constnatly. I found my house through my agents MLS system, which was about the time it showed up on the aggregates.