If you own some ultra premium domains then why not think of levying administration charges on those domain names? Because, when you own such domains, the inquiries keeps pouring. Very few are legitimate and serious and most of them are just for general knowledge. Since you don’t know which are serious and which are not you end up giving same time and preference to each and every inquiry.
The solution is to avoid it by filtering the inquires by levying cost on it. A prospective buyer must send you a payment – lets say $50 or $100 to make an inquiry. This cost will cover your time and internet cost. The main factor is your time cost. This practice keeps at bay non-serious-buyers as they will not inquire if they are not interested when price barrier is placed.
Take a look on following domains and what owners are saying about it:
HHI.com
SecuredOffers.com
I have seen many such offer pages for the Seller is demanding the ‘Offer Fee’.
I don’t think that this practice is suitable for Domainers as they’re actively seeking buyers and it’s like their routine to communicate with potential buyers for their domains. But, for NonDomainers I feel it’s necessary as they’re not actively seeking to sell the domain. And, to respond to inquires needs time and by levying administration charges they can cover the time spent on maintaining the domain name.