I was checking my referrer logs the other day and came across several peculiar entries. There were mostly weblogs (except for 1), and at first glance would seem to be legitimate. Until I noticed a few things:
- There is no sign of a link back to my site.
- There are links to smut sites which appear to be the same throughout these sites.
- The weblogs are new - in some cases there is only 1 entry, and no sign of an archive.
- Certain elements are repeated across the sites.
Unmistakably, these are sites owned by a single person (or group of persons) who is out to seek referral links back to their sites, what is colloquially called "referral spam". Whatever for, you say? Well, here's a hypothesis (obvious as it is, it probably should be called "the truth" rather than a hypothesis).
First and foremost, this person (let's just say, for ease of writing, that it is 1 person and it is a guy) is clearly someone intent on capitalizing on the weblog linking phenom that allows weblogs to have high PageRanks. A discerning eye will notice how the sites have domain names that can be turned around into sites of pornographic nature. Strong evidence that these either were porn sites before or are going to be once their Google PageRank gets high enough. By putting up some seemingly legitimate content to throw off webloggers, this person hopes to have his referral links unnoticed, unblocked (and implicitly acknowleged as legitimate). Referrer spammers are probably having a hard time with the increased awareness about referrer spam among webloggers, including tools and scripts to stop them. I can almost hear the imaginary light bulb switching on in their minds - why not use blogs as well? Place referrer links from a dummy weblog, link to several sites, get linked back (illegitimately), and get away with it. Just sit back and watch the PageRank and backlinks grow. Smart, but not smart enough.
Notice how the links to smut sites are almost consistent across all 4 sites - dead giveaway. That was what set the alarm bells ringing for me - why the hell would a weblog link to pornographic sites? In this case, this person is getting ahead of himself. The intention, as I see it, would be to make use of these fake blogs to boost search engine rankings for his existing sites by linking to them. Ah greedy, greedy. And what's more, those links go to a porn site which I've blocked. Folly, folly.
Curiousity piqued, I Googled in hope of finding someone else reporting the same phenomenon. Here's what I found:
- Ministry of Propaganda notices something strange - Blog referrer spamming?
- A preponderance of evidence does an investigation in More referrer spamming
- That last link led me to this: Porn Sites Hiding Behind Blogs
So this is not new (4 months old news isn't news). I wonder, how many webloggers have heard of this or seen this before though. I'm not clear on the how high the level of awareness is, but if you do have a weblog, do warn your readers (who are probably bloggers themselves). (And no, you don't have to link back to me - hypocrite I am not ;))
As for a solution, I use mod_rewrite to block out unwanted referrers, thanks to kasia in a nutshell. You can view my .htaccess (which contains my list of blocked referrers as well). For an explanation of how this works, check out pippo's reply to my thread at SitePoint Forums.