Analytics
Since I've started this site sometime in 1996, I've used a number of programs and sites to have access to statistics. For a long time I've used only Refer, since I was interested most in where and how people ended up on my site. Since I've had my domain (which was 2001, I think) I have also had access to the raw Apache log data via the admin panel my host offers. I've been downloading these for a while now, but, despite planning to, haven't really made a serious attempt at processing them.
And now there's Google Analytics, the result of Google buying Urchin. I signed up when I first heard of it, and am glad I did, since they're not accepting new members at the moment. I've only been trying out the service for a few days at the moment, but I must say I'm quite impressed with the way the information is presented. To be continued.