I first became aware of the Referrer Spam problem after installing and using the WordPress plugin Stat Surfer. One of Stat Surfer’s statistics categories is Top Referrers. I noticed on a business-client’s site they were getting referral traffic from porn sites and other unlikely sites. Looking into why this was happening surfaced what apparently is a widespread abuse by spammers that tie up YOUR site resources and help boost search engine rankings for the spam sites.
There are several ways to address the issue, most are relatively technical, requiring you modify code files, maintain keyword and site block-lists, etc., But fortunately because WordPress is such a popular and open platform “there’s a plugin for that…”
Bad Behaviour (British spelling I guess) address this issue with a simple to install WordPress plugin. The plugin is up-to-date (supporting the just released WordPress version 3.0.2) and has been download 184,000+ times, both criteria I use as initial screening for any plugin I am considering.
From the WordPress plugin page...
Bad Behavior complements other link spam solutions by acting as a gatekeeper, preventing spammers from ever delivering their junk, and in many cases, from ever reading your site in the first place. This keeps your site’s load down, makes your site logs cleaner, and can help prevent denial of service conditions caused by spammers.
Bad Behavior also transcends other link spam solutions by working in a completely different, unique way. Instead of merely looking at the content of potential spam, Bad Behavior analyzes the delivery method as well as the software the spammer is using. In this way, Bad Behavior can stop spam attacks even when nobody has ever seen the particular spam before.
Bad Behavior is designed to work alongside existing spam prevention services to increase their effectiveness and efficiency. Whenever possible, you should run it in combination with a more traditional spam prevention service.
One word of caution, there was a discussion on the plugin website about a bug in the most current version 2.0.38 that interferes with Google crawls that will affect your site rankings. The recommendation is to use the previous version 2.0.37 until the author tracks down and fixes the problem. Here’s the suggestion…
EXACTLY! Took me weeks to figure out, but tracing back my precipitous drop from google crawls, BB 2.0.38 must have been the culprit.
The solution: delete Bad Behavior 2.0.38 and reinstall BB 2.0.37 from http://www.bad-behavior.ioerror.us/download/
That one works and doesn’t block Googlebots as checked from within Google Webmaster central (FETCH AS GOOGLEBOT)
Suggested reading on the subject: