That's a good question. I'm not sure what is the answer. I'll do some research and get back to you if I find an useful answer. You should email the people at 123 reg as they probably could answer your 123 reg question..
But your HostGator isn't worth what you are asking. It's worth what someone is willing to pay you for it. Sometimes the parties agree, sometimes they don't..
If someone is interested in buying your domain, they'll usually either have an idea of what it's worth, or an idea of what they are willing to pay. Sure sometimes there is a little selling involved, but you'd be better off listing the reasons the HostGator is worth your asking price, rather than a worthless appraisal that offers no insight as to it's (usually very inaccurate) valuation..
Basically I'd run from any listing utilizing an appraisal, because I'd feel that the seller really has no idea what their HostGator is worth and is now deluded by some random number that has been assigned to it. No one wants to conduct business with someone whose sense of reality is skewed..
Btw, I dont mean this to be taken as a personal insult. I'm just giving my general impression and thought process when I see such a listing..
The only way I know how to appraise my domains is throw out a figure and then ask myself, "WILL someone else pay more for it?" This isn't always easy to answer, but as I stated, a HostGator is only worth what someone else will pay for it...
The only response you'd get from a reseller is a chuckle..
End user-wise, people usually have a budget in mind, and they will shop around as you've mentioned. so let's just say you list your buymylaptops.com on sedo with an automated appraisal of $10k. if your buyers can find buylaptops.com or laptops.com or notebooks.com, they will either think that they will be worth more than $10k, or think they're getting a better deal. in any case, your potential buyers will shop around and buy whichever name fits the right price, regardless of an automated appraisal..
Now if you truly owned a rare $10k domain, your buyers will realize soon enough that there isn't anything that special, and you an automated appraisal probably wouldn't help anyway...
The problem with this argument is that you can buy the exact same laptop at BestBuy, Circuitcity, Frys, ect.....
With Domains there is only 1 unique product. This is the reason price fluctuates so much. Only one business.com exists in the world, and if the owner chooses to sell it, they can ask any price in the world.....
But.... who's going to buy it at what price is not a factor they control. The sellers job is to try to get the highest possible price a buyer would pay..
Now, is price comparison a smart move for a seller? Absolutely. See what similar HostGator names have sold for to gauge what yours may be worth. But an automatic appraisal, is not "shopping around".....
My advice: do not refer to automated appraisal tools, they will only hurt your credibility..
Instead one thing you could do is look up dnsaleprice.com and try to find reported sales for similar domains. If you find decent figures then you can refer to those sales to back up your asking price..
Also if the name has traffic or the other extensions are taken when you have the .com then it doesn't hurt mentioning...
If the buyer is really interested in your name, price shouldn't be a barrier provided it's not excessively overpriced. If you feel your name is worth a minimum of 10k, saying something along the lines of "offers over $10,000 will be considered" is a good way to weed out emails from bargain hunters and resellers..
It may be useful to put a lower price (ie min offer 5k) under "what would be considered" and then try to convince the potential buyer afterwards of why your name is worth XX,XXX..
I thank everyone for their valuable points and great discussion. Keep it up!..