On the right-hand side of each item, you will see a visibility with a number. This number represents the total number of times an item has been clicked by our users.
The Trending list is determined by a pretty strightforward ratio of recency and views. Author, source, player and all other rankings are largely weighted by views.
Over the years we experimented with all sort of factors that contribute to whether or not an item is good/liked/useful. We've monitored social media shares and clicks, destination user experience, Google Search traffic to our sites to name a few. A simple tally of views proved to be by far the strongest indicator of interest/usefulness (Note: duh).
Views / Trending also largely determine which items we share on Twitter, Facebook, Tumblr and other social profiles.