If you’re like me, when you hear the word cloaking, you probably think of Star Trek, right? You know those episodes when the Klingons or Romulans employ their “Cloaking Device” to hide their ship from the Enterprise and then they appear all of a sudden and blast their unsuspecting, unaware Federation enemies to kingdom come? Yeah, that’s a cloaking device! It’s too bad they don’t make them small enough for a person!
So, what is cloaking in regards to a website? In SEO terms, cloaking is a sleight-of-hand, deceptive tactic. The term 'cloaking' is used to describe a Website that returns altered web pages to search engines that are crawling them. For example, if a regular Joe the Plumber were to visit a cloaked website, he will see and experience something different from what the search crawlers will encounter when they visit the same site. That is, the crawlers will view a more relevant, optimized site! And it is likely unreadable to human visitors. In short, the site is viewed differently by people as opposed to the search engine.
Cloaking is something that a server is programmed to do only when it sees a search engine robot visiting the site. It's called 'cloaking' because it involves hiding the content people see, and substituting it with content designed to rank higher in the search engine results pages (SERPs). Search engines have a problem with cloaking because it mocks their ranking algorithms. These algorithms rank pages with respect to what people will see on the page. When this information is deliberately withheld, or alternative information is delivered to the search engine, the algorithm cannot do its job. Cloaking is the ultimate form of invisible text---nobody sees it, not even by viewing the HTML source code.
Now, let’s address what cloaking is NOT. Personalized content delivery is not cloaking. XML feeds are not cloaking either. The common denominator in both of these examples is that neither of them hide aspects of a site from some, and reveal or make some known to others. Cloaking is only an application that exists to hide optimized content from people (in order to make them more user-friendly), and not the search engines.
Search engines strongly discourage cloaking and will penalize and even strike your site from the SERPs if you are caught using cloaking techniques. Some webmasters and programmers mistakenly think that they need to utilize cloaking to protect their website source code. What they have neglected to consider though, is that the search engines don’t care why you choose to use cloaking, they only see its use as a pattern of deception and will penalize you accordingly.
You never need to cloak. A perceived need to cloak usually indicates a more basic problem with a site. Solve those elementary problems first and you will improve your site for your visitors. A better return on investment for much less effort! So, the next time you are tempted to act like a shady Romulan or a tricksy Klingon and use cloaking---don’t! Instead, do the right thing and come out in the open like an honorable Federation Starship Captain and don’t be afraid to “engage” the enemy in broad daylight.