title: 2 approaches for tracking online users with Redis. Which one is faster?
body: <p>Recently I found an nice blog post presenting 2 approaches for tracking online users of a web site with the help of Redis.</p>
  
  <p>1) Smart-keys and setting their expiration
  <a href="http://techno-weenie.net/2010/2/3/where-s-waldo-track-user-locations-with-node-js-and-redis" rel="nofollow noreferrer">http://techno-weenie.net/2010/2/3/where-s-waldo-track-user-locations-with-node-js-and-redis</a></p>
  
  <p>2) Set-s and intersects
  <a href="http://www.lukemelia.com/blog/archives/2010/01/17/redis-in-practice-whos-online/" rel="nofollow noreferrer">http://www.lukemelia.com/blog/archives/2010/01/17/redis-in-practice-whos-online/</a></p>
  
  <p>Can you judge which one should be faster and why?</p>