Or as my friend G suggested 'Total Recull'!
Every so often I do a cull on facebook. I will announce it and people have a set time frame to interact with me. No interaction and you get deleted. In the past I have left a few people on because I know they have busy lives or don't go on facebook much but this time I stuck to the rule and went from 73 friends to 40.
However I've been thinking about it since the last cull and think I'm doing it wrong. I've deleted people that I do consider 'real life' friends. I have other ways of keeping in touch with them but facebook is a convenient way to see what they are up to, how their children are growing up etc. On the flip side I've kept people on there that I really don't know. When the notification came up that they'd commented I actually groaned as it meant I had to keep them as I was sticking to my rule. (And yes, if you are reading this from the facebook link then I might just be talking about you!)