system
A chat on subreddit /r/wallstreetbets
human
100% agree Zillow accuracy is as shitty as they come because they add their own data to the mix to make matters worse.  
  
 Zestimate is probably one of the worst offenders to calculate the property's worth. Among their other made up numbers they throw for the sheep to follow.

gpt
When I was home shopping, Zillow and Trulia were regularly  +/- $75k  off the actual asking price. These sites are fundamentally nothing more than advertising platforms accessible to people without MLS access. Real estate pros use the MLS for reliable information.