"Philly.com’sequation puts a numerical value on user engagement by calculating what percentage of the site’s users fulfill certain criteria, including viewing multiple pages, spending more than six minutes on the site, leaving comments, sharing content through social media, or returning regularly. The equation allows philly.com to track how the site is doing in terms of these individual categories of engagement, as well as averaging them out to obtain an overall engagement percentage. ... But several people ... questioned the usefulness of an equation that doesn’t take into account how user behavior affects the news organization’s bottom line ..."