Proper SEO for your website should include the judicious use of relevant and focused keywords. In indexing web pages, major search engines like Google, Yahoo!, and MSN depend on websites and their webmasters to provide appropriate keywords. However, keyword stuffing, or the overuse of keywords on a web page, can get your website banned from one or more search engines.

Keyword stuffing is not a new phenomenon. It has been used as a “blackhat” SEO technique since before Web 2.0 came along to covertly improve website search rankings. One keyword stuffing technique that major search engines are catching onto is the utilization of hidden comments that are placed out of view to users but not to search engine bots.

Uses for Hidden Comments

Hidden comments are nothing new on web page coding. Hidden comments can be utilized legitimately on a web page for accessibility or usability issues. ALT tags for images and form labels are good examples of hidden comments that help a user with the web page. Another place for comments not seen by a web page user is in the actual HTML coding. A web page author may leave an HTML comment that helps explain the code that follows for other programmers who need to read the coding. 

However, when webmasters or SEO firms use hidden comments on a web page to fill with keywords and key phrases in the sole purpose of improving search engine ranking, trouble occurs. One broad example of covert keyword stuffing is the use of cascading style sheet coding, or CSS, to add hidden comments complete with headings. An example of a hidden comment with a heading might look like this:

Keyword Keyword Keyword

Lots of text room for keyword stuffing

This coding would be seen by search engines, but not a user unless the CSS preference was turned off on the browser. Without the CSS preference, the web page would show the above text as such:

Keyword Keyword Keyword

As you can see, the coding could be a legitimate way to add helpful comments for other programmers or users with older browsers. However, when hidden comments are used in the above example to simply add keywords and not provide any helpful advice or accessibility, it is considered unethical and a form of “spamdexing,” or the use of keyword spamming in order to improve search engine indexing. 

Search Engine Policies on Hidden Text

Major search engines have written policies against spamdexing and hidden text in particular. Google, for instance, states on its webmaster guidelines:

"Quality Guidelines - Specific Recommendations: Avoid hidden text or hidden links."

Google also provides web users a place to report spam and notes on that site:

Violating our Webmaster Guidelines by means such as hidden text, deceptive cloaking or doorway pages compromises the quality of our results and degrades the search experience for everyone. We think that's a bad thing

Yahoo! has also made a very clear stance on the hidden text as spam:

Search engine spam refers to pages that are considered unwanted and appear in search results with the intent to deceive or attract clicks, with little regard for relevance or overall quality of the user experience. Some, but not all, examples include:

* Pages using methods to artificially inflate search engine ranking

* The use of text or links that are hidden from the user

These two major search engines make it very clear that using any method of hidden text to add keywords for the explicit purpose of search engine rankings is likely to get a page removed completely from their index.

Valuable Use of Hidden Comments

Where can you use hidden comments as a helpful tool?

  • META tags – Use the META “description” tag as a place to provide a short, concise comment about the website.
  • ALT tags – Some browsers may not show images, such as photos or graphics. Use an ALT tag to give a short descriptive comment about the image.
  • HTML coding – In the actual coding, you can provide comments helpful to other html programmers. 
  • CSS – In stylesheet coding, it is acceptable to use hidden comments for the purpose of accessibility or easier usability.

Keyword stuffing is not a good practice, either invisible text or hidden comments. Not only is it deceptive to users, but it can get your website removed from search engines altogether. Be sure to use hidden text and comments to help your users, not your ranking.