Free online "site value" calculators seem fairly useless, so I thought I'd ask here about educated estimations of the value of a particular domain, including the content, etc, currently live on the domain name.
The site has a global Alexa ranking of 22,040 (US: 8,469) and a Quantcast US Rank of 1,176 with a Global Daily of 59.5K. The site is educational, so traffic (and thus income) varies with the American school year.
The site is free-access with no membership; revenues come almost entirely from advertising and affiliate deals. About a third of the income comes from one particular advertiser / affiliate.
Traffic mostly comes from search engines, though there are many "good" backlinks (from universities, etc).
Revenue may creep into the six-figure range this year, but that does not take into account the fact that nobody is currently paid for services. The site is essentially a one-man office, and much of the perceived value comes from that "one man" being the "face" of the site.
The educational topic is mathematics, and a tutoring forum is currently running on the site. A buyer would need a mathematical background, or would need to hire or subcontract somebody with such, in order to manage the forum and edit / maintain the content. In order to expand the content, the original owner may need to be hired.
I've been told that the value of this site is about USD$1.8m (one-point-eight million dollars, US), but this seems to me to be a bit high (in the sense of the Pacific Ocean being "a bit" wide). I am interested in informed opinions.
Also, I would appreciate advice on reputable website appraisal services, if any exist. Thank you.