This August, the company behind the WordPress security plugin WordFence published a blog post revealing that the popular 404 to 301 plugin injected advertising into pages of the WordPress sites on which it was installed. The advertising was for low-grade and potentially scammy services like payday loan companies and escort agencies.
But if you — or the site’s owners — had visited one of the 70,000 sites using the 301 to 404 plugin, you would have seen no trace of the injected ads. That’s because the plugin’s code was sneakily designed to only show the ads when a search engine crawler loaded the page. This technique is called cloaking and it’s seriously discouraged by Google.
The facts of the 404 To 301 plugin case are interesting and have generated considerable controversy, especially with regard to the way WordFence publicized the behavior before giving the developer a chance to respond — something I find understandable given the scope of the problem and the apparently deliberately malicious ad injection.
However, I’m more interested in the general case: I have come across several WordPress site owners who don’t see the problem with cloaking.
Cloaking works by detecting the user agent of a visitor and programmatically showing or hiding content depending on whether the user is a web browser or a search engine crawler. The idea is to influence search engines — either through links or copy – to rank a page for queries for which it would otherwise not rank. It’s an attempt to trick search engines and spam their indexes.
Needless to say, search engines hate this. They want to accurately understand the contents of a page. Cloaking makes that impossible, which is why it’s against Google’s Webmaster Guidelines. If Google discovers a site engaged in cloaking, it will almost certainly be penalized.
Now, as with all of these SEO rules, site owners are free to ignore them and roll the dice on not getting caught. But if you care about Google traffic and your domain’s reputation over the long term, cloaking and related techniques are best avoided. That’s why site owners are so angry about the secretive cloaking by the 404 To 301 plugin.
What Doesn’t Count As Cloaking?
Many websites show different content to different users. They might change content based on location, audience segmentation for advertising, time of day, the user’s history and various other factors. Google does not consider this behavior cloaking. It’s important to understand that cloaking is a deliberate attempt to deceive search engines. Content personalization is not usually deceptive and almost every large site on the web does it to some degree. You shouldn’t worry that innocent personalization will have a negative impact on SEO.