The front paging algorithm explained
The front paging algorithm is very simple. Every 15 minutes the top upcoming stories in each section are examined. We automatically exclude the category, user and source that was last made popular in that section.
Each story has an invisible score that is the sum of each voter, burier and commenter’s SiftKarma at the time that they committed the action on that story. From that score and the age of the story we calculate the momentum each story has and if it is greater than or equal to the threshold for that section then it is made popular.
The threshold for each section is a sliding scale. It is 20% less than the score that was previously made popular in that section. If no submissions meet that criteria it is reduced by 20% to lower the barrier for the next time the software runs 15 minutes later.
For making stories featured we follow the same process but by examining stories that have been made popular in the last 2 hours.
