Yahoo SEO – Thinking About class=”robots-nocontent”

The “robots-nocontent” class attribute is a non robots.org standard supported by Yahoo only and launched in May 2007. The sole purpose of this attribute is to allow the webmaster to highlight areas of content that are considered irrelevant to the main subject of the page to Yahoo’s crawler, Slurp.

There hasn’t been much noise (if any) about the use of robots=”nocontent” since it’s launch, but I thought I’d take a look at this “class” attribute as part of my SEO research and do some tests on my site to see if it made any actual difference.

Why would a search engine ask webmasters to use a class attribute in their on-page SEO?

Often, large amounts of “clutter” can get in the way of the “core” topic of the page. It makes sense that a search engine may choose to publish a tag that allows a section of a page to be disregarded from the relevancy calculations in their algorithm, particulary if that page would otherwise be littered with blocks that contain irrelevant, duplicate or navigational content.

If you need some (excellent) background on block analysis theory, I strongly recommend you read Tim Nash’s post on block segmentation analysis.

How do you apply the robots=”nocontent” attribute?

“robots-nocontent” can be applied as a class attribute in a header, div, span, or paragraph container. For example:

<h2 class="robots-nocontent">purplemonkeydishwasher</h2>

<div class="robots-nocontent"> purplemonkeydishwasher </div>

<span class="robots-nocontent"> <h2>purplemonkeydishwasher</h2> </span>

<p class="robots-nocontent"> <h2>purplemonkeydishwasher</h2> </p>

How to Display the Robots-Nocontent Hidden CSS Class in Firefox

1. Go to and Install the Chrone Edit Plus Firefox Extension 2. Restart Firefox 3. Go to Tools->ChromeEdit Plus->ChromEdit. Select the userContent.css tab and paste the following code in plain text:

a[rel~="nofollow"] { border: thin dashed firebrick ! important; background-color: rgb(255, 200, 200) ! important; } .robots-nocontent { border: thin dashed firebrick ! important; background-color: rgb(200, 255, 200) ! important; }

4. Restart Firefox (again)

So what?

My theory is that if a search engine has a weak relevancy algorithm, or at least the block analysis element of the algo needs work then code elements such as robots=”nocontent” should improve upon (and support) the algorithm. If a search engine relies on a webmaster for “help” with determining the location of simple items such as a navigational bar then it stands to reason the use of this code can easily be exploited. Perhaps that’s why Google does not (apparently) support the nocontent attribute.

As far as my test goes, so far, results are positive for the rankings I’ve been watching for SEOgadget. Traffic is growing nicely too, but I’ll be the first to admit growth in rankings and traffic could be down to a number of other variables. I can say that the inclusion of robots=”nocontent” has not impacted me detrimentally. My Yahoo traffic is growing and Google referrals have (so far) been unaffected:

robots=nocontent yahoo experiment

My recommendation is this. All sites are different. Even WordPress sites are laid out depending on the theme that has been designed, so the best course of action to take is implement the code yourself and study your Yahoo traffic to see if there’s a positive impact. Just to be on the safe side, leave at least some of your blog taxonomy open to indexing or create an indexable sitemap. That way, you won’t accidentally orphan half of your website!



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