A buddy at work sent out the following link which proved to be an interesting read and should be read by any developer supporting a high traffic website.

http://highscalability.com/blog/2010/3/23/digg-4000-performance-increase-by-sorting-in-php-rather-than.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+HighScalability+%28High+Scalability%29