For the impatient:
Patch for Webalizer 2.01-10
Webalizer source
Google’s nofollow
page
The latest salvo in the battle against referrer spam and comment spam is nofollow, an HTML tag that instructs search engines not to count a link in their algorithms. It’s not much, but for my part, I’ve written a trivial patch that adds nofollow support to webalizer, a popular web server log analyzer.