Recently, rustybrick at SEO Roundtable mentioned that some publishers are selling links, but then adding cloaked nofollows. That is: The links appear to “follow” and pass page rank to normal visitors, but say “nofollow” to Google.
Clearly, this sort of “nofollow” is lessens the value to advertisers who think they are paying for the both link juice and traffic, but get traffic only.
This type of cloaking is fairly easy to do. But, I want to warn any ninja bloggers out there: it’s also it’s easy to catch! 
How can advertisers detect cloaked no follows?
There are two ways: One is quick, and will often work; the second takes more time, but is more effective.
Here’s how:
- Visit pages using User Agent Switcher and Search Status:
Search Status makes “nofollow” links easy to detect by highlighting them in pink. User Agent Switcher lets switch your “user agent” to “Googlebot” and surf the web seeing it the way the Googlebot does (at least usually.)Used together, you should be able to catch most publishers who cloak to show “nofollows” only to the Googlebot. If you use both, you will usually see all cloaked nofollows will be shown in pink when you set your user agent to Googlebot. They will not be pink when you set your user agent to default.
Unfortunately, this method is not foolproof, because a) Spam plugins like Bad Behavior will notice you aren’t really the Googlebot and refuse to show you the pages. This is an entirely legitimate way for a publisher to protect their page. b) Some “clever” publishers may cloak by detecting IP in addition to user agent. This could foil detection using the User Agent Switcher.
Luckily, you can always rely on method 2:
- Check cached page at Google: Periodically, while the your contract is in place, visit Google and check the cached copy of all pages with paid links. Obviously, if the Googlebot is shown “nofollows”, it will cache a page containing nofollows. So, this method is foolproof.
Will I be writing a cloaking plugin?
I’m tempted to write a cloaking extension to NoOldSpamLinks plugin. It would be great for traffic. But, I’ve decided against it.
I’m all for letting bloggers control their nofollows. I think bloggers should be able to do whatever they prefer with their links within the law and contractual obligation.
But, I’m afraid I can’t bring myself to help bloggers show “follows” to advertisers who pay for them, and “nofollows” to Google. If you want to sell “nofollow” links, negotiate that with the advertiser; then show the nofollows to both the public and Google. If you as a blogger want to cloak to show nofollow to Google, and “follow” to your paying customers, I’m not telling you how to do it!