IMO it depends on the site and whether or not the number of users correlate directly with income. For instance, i've worked on a few microsites for brands that

IMO it depends on the site and whether or not the number of users correlate directly with income. For instance, i've worked on a few microsites for brands that report number of users on the site as a form of social proof. On the other hand large services that announce their numbers might persuade more companies to enter the space.