Referral spamming test

Referrer spamming

When the search engines promoted the “no follow” tag earlier this year, I feared webmasters would see a deluge of referrer spam.

Referrer spam is when a script is used to send a bot to access websites, and uses a predetermined URL as a fake referrer string.

In other words, you can run software that makes other websites think you are sending them lots of visitors, and will show up in their logs - but it’s all entirely fake.

Why referrer spam?

The reasons for doing this are two-fold:

• Lots of sites leave their site stats open to search engine crawlers - so you can gain crawlable links from valuable university and government sites easily;
• You can gain significant traffic from webmasters checking their logs, finding you in the referrer lists, and clicking through to see what you’re saying about them.

It’s a nasty tactic, and the cost is entirely to the webmaster by way of their bandwidth being used up by fake visitors.

IP blocking is no good, as any half-decent referral spam script will use open proxies - insecure computer networks - as a means of delivery.

Referral spamming - how common?

I’ve certainly seen an increase in referral spamming over the year, but nowhere as much as I feared.

It’s a mixture, too - there are a slew of gambling, porn, and pharmaceutical domains in the logs of all of my sites, though none of my sites have their stats publically available.

There are surprises, too, as legitimate sites get caught up. I’ve found Jill Whalen’s High Rankings forum used as a fake referrer string on multiple sites.

As Jill has been the target of some quite vindictive attacks by small groups of SEO’s in the past, it’s easy to see how referrer spamming can be used in an attempt to damage the reputation of other sites.

Point being, not all referrer spam can be presumed to be originated from the fake referrers.

How effective is referrer spamming?

Referrer spamming can certainly generate traffic - the most aggressive offender I see on a lot of my domains is “jaja-jak-globusy” dot com, which has no content, but has an Alexa ranking in the 40 thousands.

Does it work for SEO purposes, though? I wanted to test this directly.

In all honesty, it’s not something I want to be a part of my business model, but oftentimes in SEO simply being aware of how a process works is more important than using it.

Testing referral spam

At the beginning of September I used Google to search for sites that allowed their webstats to be crawled - simply searching for core phrases on the popular Webalizer stats program led to significant number of targets.

I then set up a new domain in a very competitive topic area, and put some unique content on it.

Using a relatively cheap referral spamming script, I then directed it via open proxies to fake the new domain as a referrer to the sites in question - and ensured that the domain was listed in the site stats.

A number of .edu and .gov sites were included in targeting, not least because of their known significance for Google.

Referrer spamming: the results

After 14 weeks I checked back on the domain. The results speak for themselves:

Google

Google has not indexed the site. The domain is absent for a search for itself, and there is no cache record. Google obviously ignores at least the most basic referral spam methods - they may index stats pages, but know to ignore them. Although I set up AdSense on the site, the AdSense Mediabot visited but Googlebot never came by.

Yahoo!

Yahoo! has indexed the site, cached it, and it is present in the index. Yahoo! seems to have been especially keen to index the RSS files associated with the site. Traffic from Yahoo! has been zero, though, so the low level of referrer spamming I performed only helped with indexing for Yahoo!, not ranking.

MSN

MSN has no record of the site. The domain is absent for a search for itself, and there is no cache record. However, it’s difficult to determine whether MSN didn’t list the site because it purposefully doesn’t crawl stats, or simply because of reported deep indexing problems that are known with that crawler.

Interestingly enough, a bot for Netcraft also found the site and set it up in their records.

Conclusion

Low level referrer spamming has no SEO benefit - it’s a problem that Google has already addressed, MSN may not be able to cope with - and isn;t going to be of great benefit for Yahoo! other than for indexing purposes (and there are simply ways of being indexed by Yahoo! anyway).

As noted by the example of the domain jaja-jak-globusy dot com, though, a very aggressive referral spam campaign will generate significant - if untargeted - traffic. However, referrer spamming for traffic purposes can only be a very inefficient method of gaining traffic because of its lack of targeting.

Overall, if you want traffic to your site, and targeted traffic at that, there are far easier - and less offensive - methods of gaining it. So far as this test suggests, at least basic referral spamming is a tactic of very little value.