zillowed

I just went through the whole zillow 'Post for Sale' process for a listing of mine and I found it to be very easy to do (or so I thought) - I read all the instructions, filled in all the info, uploaded the photos, answered all the questions, agreed to all the terms, clicked Submit and - zap, zilch, nothing. Apparently zillow didn't like my listing. It didn't take and it's lost somewhere in the zillow vapor. Then I got a little paranoid and started wondering if getting zapped was pay-back for my past criticism of zillow. Who knows.
As an interesting aside though, the zestimate for this property is $542,806 and my list price is $535,000 (which I believe is right-on). And, I originally listed this property at $549,000 , which puts the zestimate almost dead-center between my original and revised list prices. The atypical accuracy of this particular zestimate is one of the reasons why I went ahead and listed - or tried to list - the property on zillow? But I thought it was odd and awfully coincidental for the zestimate to suddenly be this accurate, and on a listing of mine, which is by far the closest I've seen a zestimate come to real world values since I started criticizing zillow for its lack of accuracy, amongst other things. Or, wait a minute, could it be the other way round, and zillows zestimate is based on my list prices?