Zillow valuations fact or fiction

[Douglas W. Rink]

I've come to realize that Zillow is (strives to be) the "starbucks" of Real Estate.  Do they have some special some special algorithm that can give them such accuracy on their "Zestimate" like Google uses in it's search advertisements?  Are appraisers doomed?  Will Lenders of the future use the Zestimate instead?  How close are Zillow valuations to actual in your area?