title: Using Redis for "trending now" functionality
body: <p>I'm working on a very high throughput site with many items, am looking into implementing "trending now" type functionality,  that would allow users to quickly get a prioritized list of the top N items that have been viewed recently by many people, that gradually fade away as they get fewer views.</p>
  
  <p>One idea about how to do this is to give more weight to recent views of an item, something like a weight of 16 for every view of an item the past 15 minutes,  a weight of 8 for every view of an item in the past 1 hour,  a weight of 4 for things in the past 4 hours, etc but I do not know if this is the right way to approach it.</p>
  
  <p>I'd like to do this in Redis,  we've had good success with Redis in the past for other projects.</p>
  
  <p><strong>What is the best way to do this,  both technologically and the determination of what is trending?</strong></p>
  
  <p>The first answer hints at a solution but I'm looking for more detail -- starting a bounty.</p>
  
  <p>These are both decent ideas,  but not quite detailed enough.    One got half the bounty but leaving the question open.</p>