Forum Module

The Forum Module is part of Drupal core. If you enable the Forum Module, there are some things to be aware of.

Whenever Web sites create tables that are sortable by column headers, you are looking at potential duplicate content.

The image above shows table headers in Drupal's Forum Module. When you click on one of those links, it re-sorts the data in the table appending parameters to the original URL.

In the example image above, the original URL structure is http://example.com/forums/introduce-yourself. Drupal's Forum Module creates the following additional URLs in the header links:

After visiting those pages you (and spiders) will also find the following URLs:

Pagination of the forums makes it even worse because each page can then be sorted in these 8 ways. Here is one example from Drupal.org: http://drupal.org/forum/2?sort=asc&order=Last+reply&page=393.

SEO Recommendation for the Forum Module

The recommended fix for this problem is to add the following line to the robots.txt file:

Disallow: /*sort=

SEO Recommendations for Drupal Core

The following line should be added to the default Drupal robots.txt file because the Forum Module is distributed with Drupal:

Disallow: /*sort=