How Session Id's Can Cause Duplicate Content

[peter_d]

From Google WebmasterCentral:

http://googlewebmastercentral.blogsp...ed-by-url.html

When user and/or tracking information is stored through URL parameters, duplicate content can arise because the same page is accessible through numerous URLs.

And what to do about it?

1. Removing unnecessary URL parameters -- keep the URL as clean as possible.

2. Submitting a Sitemap with the canonical (i.e. representative) version of each URL. While we can't guarantee that our algorithms will display the Sitemap's URL in search results, it's helpful to indicate the canonical preference.

[Natural Elements]

Hello Peter,

I had this session ID's problem before with Google. You cannot clean the urls because the cart system was made for session ID's, when it was possible to help search engines with search engine friendly urls, the modifications duplicated the page products by two.

The session ID's are still live in background, but after creating a .Xml sitemap and canonical preference, fixed the problem.

I cannot use 301 htaccess and I don't see myself to redirect all product pages.

It is impossible to work with Yahoo, and Alexa, I contacted them long time ago with no succes, and I am sure they don't care.

You cannot change your system cart after each search engines SEO updates, or hot for SEO purpose.

I found using robots.txt work only with Google.

[brandrocker]

Thanks for pointing to that. This is one of the most common technical problem that may invite a penalty. I had similar problem with one of my websites. I tried for different hacks to remove session IDs. I had at that time two different urls for my home page indexed (luckily not banned) - one with session ID and another without session ID.

Please read this discussion for removing session IDs
http://www.astahost.com/info.php/nee...rl_t11358.html

[kaykays]

I had a problem on one of my web-sites where I found that URLs
with Session IDs are created automatically for all PHP page which
used the PHP function session_start();

To correct this problem, I removed this function from all pages
which were to be spidered, and let it remain only on pages viewable
after Login. I also did a 301 redirect from URLs with session ids to
urls without session ids. This corrected the problem.

[brandrocker]

Correct kaykays. That's also a good way to get rid of unwanted session IDs.