CGI Parameters: should we worry about duplicate content?

[jackson_lo]

Hi,

My question is directed to CGI Parameters. I was able to dig up a bit of content on this but I want to make sure I understand the concept of CGI parameters and how they can affect indexing pages.

Here are two pages:

No CGI parameter appended to end of the URL:

http://www.nytimes.com/2011/04/13/world/asia/13japan.html

CGI parameter appended to the end of the URL:

http://www.nytimes.com/2011/04/13/world/asia/13japan.html?pagewanted=2&ref=homepage&src=mv

Questions:

Can we safely say that CGI parameters = URL parameters that append to the end of a URL? Or are they different? And given that you have rel canonical implemented correctly on your pages, search engines will move ahead and index only the URL that is specified in that tag?

Thanks in advance for giving your insights. Look forward to your response.

Best regards,

Jackson

[stevenmusumeche]

Since it is a duplicate and meant for mobile devices, then yes, I would use a canonical tag or even noindex if you don't want it in the index anyway.  Either method would eliminate the duplicate content problem.

[jackson_lo]

The page content is the exact same, the the layout is built for a mobile device. So in essence we don't know why it would be indexed, unless that happens for mobile browsing pages...

So the solution is to put a rel-canonical tag on that trailing parameter page to prevent duplicate content.

[stevenmusumeche]

Is the page with device=iphone&c=y different than example.html?  If not, you should make sure to add the canonical tag to it.  If it is different, then you shouldn't add it because it's not a duplicate.

[jackson_lo]

Hi Steve,

Another thing I came across... a page with trailing parameters like ?device=iphone&c=y is rendering a different set of code. So we have the original page with the content, and then we have www.example.html?device=iphone&c=y. The one with the trailing parameter doesn't have a canonical tag attached to it, but it's indexed in Google (when we search the www.example.html URL) it shows up as number two.

Do you have any insights into this? Will this be a duplicate content issue?

Thanks!

Jackson

[jackson_lo]

Thank you Steve for your response. I had come across Dr. Pete's post in the past but forgot about it. Nonetheless, the CGI parameter explanation and the use of canonical tags answers my question.

Jackson

[stevenmusumeche]

Yes, you can say CGI parameters = URL parameters.  I don't think many people refer to them as CGI parameters anymore though.

To answer your question, yes, as long as you have rel canonical set up correctly, then the URL parameters won't hurt your indexing.

For example, if you have your rel canonical set to http://mysite.com/japan.html

Then, only that page will be indexed, even if there are various parameters such as

http://mysite.com/japan.html?source=something&whateva=somethingelse

Just MAKE SURE to setup rel canonical correctly because it can be bad if you don't.  Check out Dr. Pete's post about this: http://www.seomoz.org/blog/catastrophic-canonicalization