Referrer spam is all those entries you see in your web server's referrer log that indicate that people are coming to your site from web pages that don't really link to you. It's left there in the hope that your referrer logs will be visible to Google and friends, and that you (and your site's visitors, if your referrer logs are exposed) will see it, think "I wonder what's on this page that's linking to me", and visit their site. Well, my referrer logs are not exposed, and while I do sometimes visit sites that I find in my referrer log, I do not visit the kinds of sites that perpetrate referrer spam. They're easy to spot.

Referrer spam is a lot like email spam in that way--if the domain name has words like "viagara", "blackjack", "casino", "diet pills", etc. in it, my eyes have been trained to ignore it like a banner ad. If that's the case, why does referrer spam bother me at all? Because it reduces the value of my server logs by making it harder to see the legitimate referrers that I'm trying to find, and by artificially pumping my traffic statistics. So today, I take action.

Caveat Lector has an article describing a few techniques that can be used to block referrer spam. I'll be using my own list of words to block. I look forward to the cleanup of my logs.