The Dynamic URLs tab is available for authenticated sites and allows a site owner to provide Yahoo! Search information about the dynamic parameters available on their site. You might use URL parameters in your site to perform various functions apart from modifying the content of the page, such as:

• session ids - for tracking user sessions
• source trackers - for tracking the sources which are sending referrals to your pages and site
• format modifiers - for print formats etc

In these cases, our crawler will come across different versions of your site's URLs that are substantially, if not exactly, similar in content. This causes numerous problems:

1. Such URLs look like different documents to our crawler and create excessive crawling on your site.
2. We do our best to detect duplicates among these pages, and the detected duplicates are prevented from ranking well. However, if we are unable to detect the duplicate, this results in duplicate results from your site competing for positions in search results
3. When people link to your site with different versions of these URLs, it fragments the link referrals to your site across multiple different URLs even though it's the same page.

This feature allows you to specify what parameters on your site are dynamic parameters that are content-neutral (that is, they do not effect the content on the page) and are present for other uses. To help you get started, we also show you the parameters that we found as possible candidates in our analysis of your site crawl. You can select one of these parameters and provide actions for them.

We can use this information to reverse the adverse effects mentioned above.