A business's value is based on a few factors often consisting of a multiple of EBIDTA or Gross Revenue (depnding upon the industry). It also can be based on brand value and the potential of licensing agreements, distribution channels, etc. That website has none of that data since most companies are private and their books are not open. The value they have listed there probably has to do with web visits and the value of the site from a marketing standpoint (ie, selling advertising space).
It is not the value of that business or any business you have listed.