Maximise » Yahoo http://www.maximise.ie Get found on the web. Mon, 24 May 2010 00:46:20 +0000 en hourly 1 http://wordpress.org/?v=3.0.1 Prevent duplicate content problems with canonical tags http://www.maximise.ie/blog/032009-the-canonical-tag http://www.maximise.ie/blog/032009-the-canonical-tag#comments Thu, 12 Mar 2009 23:55:46 +0000 Daragh http://www.maximise.ie/?p=110 Duplicate URLs pointing the same content can mean that different versions of the same page end up competing with each other in the search results, meaning that no one page gets gets placed well.

All of these URLs could point to exactly the same content:

  • http://example.ie
  • http://example.ie/index.php
  • http://www.example.ie
  • http://www.example.ie/index.php


    • If you’re running any online ad campaigns, by the time we take into account campaign tracking tags, like these:

  • http://www.maximise.ie/index.php?campaign_id=35
  • http://www.maximise.ie/index.php?campaign_id=36


    • - there may be hundreds or even thousands of URLs all pointing at the same content with slightly differing URLs.

    Why is this a problem? Search engines see these as different pages, despite the identical content. They try to get it right, but don’t always succeed.

    The power of your inbound links is diluted because the Google is treating each variant of the URL as a unique page.

    In a rare joint effort to help webmasters (and themselves) with this problem, and also to help clean up the search results, the major search engines have collaborated on a solution and the result is the canonical tag. This is a meta tag placed into the the HTML of your page with the canonical, or master, version of your URL.

    If one of your URL variants looked something like this:

  • www.example.com/index.php?campaign_id=35


    • - you would probably want to make the canonical URL:

  • http://www.example.com



    • How to place a canonical tag in your page.

    Place your canonical tag in the <head> section of the HTML of your page, and it should look like this:

    <link rel=”canonical” href=”http://www.example.com/”>

    Next time your page gets crawled, the score which would previously have been assigned to the variant URL is now assigned to the one true canonical, version of your URL – solving the problem of duplicate content and resulting in a higher search result position.

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