Last week Rick Latona sold the domain (and small website) FollyBeach.com for $98,000. This is a high price for this domain in my opinion - Folly Beach is a beach town in South Carolina, but is not a major tourist destination. A key piece of the sale was probably the fact that this website was making $20 per day with Adsense (largely due to high google rankings) - and that is where the world of domainers and webmasters collides.
Many domainers will pay 5 to 10+ years earnings for domains that have natural type in traffic. They look at these names and assume this type in traffic will keep on coming for years and years and that this traffic is simply an annuity. Whoever bought this domain saw a very nice geo domain (a nice value in and of itself) but they also saw $20 per day and probably used a bit of domainer math to rationalize the $98,000 asking price.
Webmasters on the other are much more likely to buy and sell sites based on 10 months earnings than 10 years (understanding the ups and downs of Google etc). It all depends on the domain and the web site history, but multiples for buying and selling websites are generally closer to 6 months -3 years.
What this means:
Webmasters - If your site is on a decent domain, head over to the domain forums, double your price and sell your site there before you sell it on sitepoint.
Domainers - Develop your generic .com domains, get a bit of search traffic coming to your domain and you could double the value of your domain with minimal work. Spend some real time on your site and you might be able to increase the value of your site 5x or more….