cr1t1calh1t - 9:43 pm on Dec 8, 2011 (gmt 0)
Just how much value does the 'face' of the site represent?
This might not be that big of a deal, though - as every buyer is different, and with different motivations for buying. While the revenue from the site represents its value to you (an assumption), a buyer could be interested in the site for reasons that might not be readily apparent to you - reasons that might not need the 'face' of the site - such as branding, strategic value within their industry, adding a new product or offering to their current line instead of building it themselves, etc...
If you can quantify the value of the 'face' of the site you're getting closer to a 'better' valuation, keeping in mind the motivations of the buyer, and your motivation for selling. Unless this personality *is* the site, I wouldn't consider this to be that big of a factor in my own internal valuation. Everyone is replaceable...
If they're focused on revenues, I would posit that a buyer of a website in the six-figure+ price range would probably use a more sophisticated model than a raw multiple, such as a discounted cash flow model. Examine 1-3 years of revenue and traffic data, use this to discern a growth rate (if any) that can be realistically applied to future revenue for a 3-5 year time horizon, then apply a discount rate that represents your thoughts on the risk involved with that stream of revenue.
I don't know of any website appraisal services that I would recommend. The market for revenue producing websites is illiquid and lacks any kind of transparency. The unknown motivations of the buyers and sellers, and the complete absence of verifiable sales data in this market makes it difficult for a third party to place a realistic valuation on a website.