Estibot and all automated appraisal services are pointless and useless IMO.
Domaining is simple. A domain is worth precisely what anyone is prepared to pay for it. No more, no less. You got 100 domains at Afternic with no bids? You have a worthless portfolio. Someone buys brgrrrem.org for $55 - guess what, brgrrrem.org was worth $55.
It really ain't rocket science.
If EstiNot appraises your domain at $4,500 and it doesn't sell well....is it worth $4,500??? Now (like many here) you can kid yourselves that it IS worth that but you 'just ain't found the right end user yet' (yep, that old chestnut is a popular one). Or alternatively, maybe it ain't worth what the bot says and the reason it hasn't sold is because it's not very good. Yes, really! That is a possibility.
Why am I so anti automated appraisals? All it does is make people with bad domains feel better about them. This in turn encourages them to go out and waste more money on bad regs. I really don't like to see people waste money. Unfortunately, it takes alot to prize a domainer away from his vanity (which might explain why I get so much abuse for simply telling it like it is and actually trying to help dudes out with a bit of honest, homespun truth!).
If anyone needs an automated appraisal on a domain, they should find another hobby IMO.
Just to conclude:
Some random Estinot appraisals I just did...
Melbourne.com - Estinot says 130K - sold for 700K (oh well, only 570K out)
WeldingRobots.com - Estinot says 20k - sold for 50K (oh well, only 30K out)
Hotel.mobi - Esti 5.5K - sold for 46K (40K out....oh well)
nhainc.com - Esti 80 (eighty dollars) - sold for 2.5K (well not so far out at least)
In fact, I just did loads more and they were all out apart from Brisbane.com which was spot on (well done!). Some did get closer than others. If anyone would like me to post further comparison examples I would be happy to do so or you go to DN journal look up some recent sales and play the game yourself.
This is just the sort of random game you are playing when you enter your domain in the box for an automated appraisal.
Just PM me, I will give you a much more accurate appraisal.