The Zestimate is arguably the most popular — and polarizing — number in real estate. An entire generation of homeowners doesn't know life without the algorithm; some obsessively track its output as they would a stock portfolio or the price of bitcoin... Many industry insiders regard the number as a starting point at best and dangerously misguided at worst. Real-estate agents recount arguments with sellers who reject their pricing advice, choosing to take the Zestimate as the word of God. One meme likens its disciples to adults who still believe in Santa. Zillow itself lost hundreds of millions of dollars...