noindex

The noindex value of an HTML robots meta tag requests that automated Internet bots avoid indexing a web page.[1][2] Reasons why one might want to use this meta tag include advising robots not to index a very large database, webpages that are very transitory, pages that one wishes to keep slightly more private, or the printer and mobile-friendly versions of pages. Since the burden of honoring a website's noindex tag lies with the author of the search robot, sometimes these tags are ignored. Also the interpretation of the noindex tag is sometimes slightly different from one search engine company to the next.

Noindexing entire pages 

<html>
<head>
  <meta name="robots" content="noindex">
  <title>Don't index this page</title>
</head>

Possible values for the meta tag content are: "none", "all", "index", "noindex", "nofollow", and "follow". A combination of the values is also possible,[1] for example:

<meta name="robots" content="noindex, follow">

Bot-specific directives

The noindex directive can be restricted only to certain bots by specifying a different "name" value in the meta tag.

For example, to specifically block Google's bot,[3] specify: 

<meta name="googlebot" content="noindex">

Or, to block Yahoo!'s bot,[4] specify: 

<meta name="slurp" content="noindex">

Or, to block MSN's bot, specify: 

<meta name="msnbot" content="noindex">

robots.txt file

Entire Web pages can also be noindexed using a robots.txt file.

Noindexing part of a page

It is also possible to exclude part of a Web page, for example navigation text, from being indexed rather than the whole page. There are various techniques for doing this; it is possible to use several in combination. Google's main indexing spider, Googlebot, is not known to recognize any of these techniques.

<noindex> tag

The Russian search engine Yandex introduced a new <noindex> tag which prevents indexing of the content between the tags. To allow the source code to validate, <!--noindex--> alternatively can be used:[5]

<p>
Do index this text.
<noindex>Don't index this text.</noindex>
<!--noindex-->Don't index this text.<!--/noindex-->
</p>

Other indexing spiders also recognize the <noindex> tag, including Atomz.[6]

microformat

There is a 2005 draft microformats specification with the same functionality. The Robot Exclusion Profile looks for the attribute value class="robots-noindex" in HTML tags:[7]

<p>Do index this text.</p>
<div class="robots-noindex">Don't index this text.</div>
<span class="robots-noindex">Don't index this text.</span>
<p class="robots-noindex">Don't index this text.</p>

A combination of values is also possible,[7] for example:

<div class="robots-noindex robots-follow">Text.</div>

Yahoo!

In 2007, Yahoo! introduced similar functionality to the microformat into its spider. However, Yahoo!'s spider is incompatible in that it looks for the attribute value class="robots-nocontent" and only this value:[8]

<p>Do index this text.</p>
<div class="robots-nocontent">Don't index this text.</div>
<span class="robots-nocontent">Don't index this text.</span>
<p class="robots-nocontent">Don't index this text.</p>

Structured comments

The Google Search Appliance uses structured comments:[9]

<p>
Do index this text.
<!--googleoff: all-->
Don't index this text.
<!--googleon: all-->
</p>

Other indexing spiders use their own structured comments.

See also

References

  1. 1 2 Robots and the META element, Official W3 specification
  2. ↑ About the Robots <META> tag
  3. ↑ Using meta tags to block access to your site, Google Webmasters Tools Help
  4. ↑ How to Prevent Yahoo! Search From Indexing Specific Pages, Yahoo! Search Help
  5. ↑ "Using HTML tags". webmaster → help. Yandex. Section: <noindex> tag. Retrieved March 25, 2013.
  6. ↑ "General Search FAQ". Help. Atomz. 2013. Section: How do I exclude parts of my site from being searched?. Retrieved March 23, 2013. Need to prevent parts of individual pages from being searched? If you want to exclude portions of a page from indexing, surround the text with <noindex> and </noindex> tags. This is useful, for example, if you want to exclude navigation text from searches.(registration required)
  7. 1 2 Janes, Peter (June 18, 2005). "Robot Exclusion Profile". Microformats. Retrieved March 24, 2013.
  8. ↑ Garg, Priyank (May 2, 2007). "Introducing Robots-Nocontent for Page Sections". Yahoo! Search Blog. Yahoo!. Retrieved March 23, 2013.
  9. ↑ "Administering Crawl: Preparing for a Crawl". Google Search Appliance. Google Inc. August 23, 2012. Section: Excluding Unwanted Text from the Index. Archived from the original on November 23, 2012. Retrieved March 23, 2013.
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