I wonder what its calculated based on.
i think its hilarious that its 'most viewed sites in the US' list is 99% porn sites, lol.
How it works?
Websiteoutlook contains a collection of actual number of pageview from other websites. The visitor data is combined with information about number of links that point towards the site, country, Alexa ranking and other data that is available on-line. All this information has been used to make a formula that uses the information that is available on-line to estimate the number of pageviews, its worth and possible daily incom that the site has.
Sadly this is not worth much in terms of accurate data. Especially nowdays where many sites use no-follow etc and external links do not always work.
For reference I have just checked it against one of my sites - the shown value is less than what the site actually brings in EACH MONTH in terms of ad revenue.
Domain business is hard to predict and the real value can barely be calculated by using a formula.