title: How do I calculate popularity of content?
body: <p>I'm developing a web site where the user rates content (1-5 stars). I need to measure the popularity of the content (also referred to as importance/hotness/interest). My first thought was just to add the user ratings for a content: </p>
  
  <p>Popularity = SUM(Rating - 2.5)</p>
  
  <p>If two users gives it 5-stars and one gives it 2 stars it gets popularity of 2.5+2.5-0.5 = 4.5. The value then gets dampened depending on how old the content is. I want it to be as accurate as possible so I'm wondering if this is "good enough" or if there is a better way by e.g. analyzing the distribution of ratings, or if I must bring in more metrics (views, comments, shares, time spent on content etc.).</p>