Referrer spam – or by Apache’s original misspelling, referer spam – has been a problem at snarfed.org for years. My webalizer logs were publicly accessible at one point, so spammers targeted this site with fake referrers, hoping that they’ll be linked from the pages that webalizer generates.
There are a number of approaches to fighting referrer spam, but so far, no silver bullet. I currently handle it a hand-edited blacklist of known spammer’s sites. It’s far from ideal, but it works. You can find my blacklist in my webalizer.conf file. If you’re fighting referrer spam too, feel free to borrow it.