Have you ever wondered why most of the posts on Reddit’s front page are less than 12 hours old? Or why a post with a score of 4,000 is ranked below a 3,000-score post? It all has to do with Reddit’s window of virality.
Each post on Reddit has a score attached to it: score = upvotes – downvotes. Reddit’s “hotness” algorithm uses this score in combination with the post’s age to rank every single post on Reddit.
Amir Salihefendic wrote a fantastic post explaining the nitty-gritty of how Reddit’s hotness algorithm works, so I won’t bother repeating that here. Instead, I’ll jump right into the visualization showing us Reddit’s window of virality.