Maile Ohye has an excellent writeup scanning various duplicate content issues caused by URL parameters on the Google Webmaster Central blog.
How can URL parameters, like session IDs or tracking IDs, cause duplicate content?
When user and/or tracking information is stored through URL parameters, duplicate content can arise because the same page is accessible through numerous URLs. It’s what Adam Lasnik referred to in “Deftly Dealing with Duplicate Content” as “store items shown (and — worse yet — linked) via multiple distinct URLs.”
Why should you care?
When search engines crawl identical content through varied URLs, there may be several negative effects:1. Having multiple URLs can dilute link popularity. For example, in the diagram above, rather than 50 links to your intended display URL, the 50 links may be divided three ways among the three distinct URLs.
2. Search results may display user-unfriendly URLs (long URLs with tracking IDs, session IDs)
* Decreases chances of user selecting the listing
* Offsets branding efforts
Comments
6 responses so far ↓
Pozycjonowanie on Sep 13, 2007 at 5:26 am
thanks for news Loren I always try to watch overe the duplicate but sometimes it’s a problem but when website is on google tools it’s easy to change from www or not in the url. Regards
Ken Savage on Sep 13, 2007 at 2:54 pm
we have a problem with this as we are tracking clicks from our RSS feed as well as the original article.
The rss feed we give a few parameters to track that it came from the feed as well as what campaign effort gets the credit for the traffic.
bob on Feb 10, 2008 at 12:53 pm
Zm3b0y hi great site thx http://peace.com
Celebrity on Jun 12, 2008 at 6:24 pm
wow thats very informative, i never realized having multiple urls for the same site to be bad.
celebrity on Feb 13, 2009 at 6:24 am
Very interesting article.Good work
sexy on Feb 16, 2009 at 3:13 am
Thanks for very interesting article.
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