Accessible URLs

Session Identifiers

Another potential concern with URLs is the use of so called “session identifiers”.  A session identifier is a unique value that some websites assign to each visitor (including search engine robots) when they enter a site and is often appended to a webpage’s URL.  These identifiers are intended to aid in research gathering by allowing the web marketer to track individual visitors as they maneuver through the site. 

However, from a search engine’s point of view the inclusion of a unique session ID within the URL signals to the search engine that a new webpage exists since there is a new, unique URL.  Even though the page content is the same for all visitors to a page, the addition of the session ID to the URL suggests to search engines that a new page is now available on the site and, thus, is indexed as a new page.

Unfortunately, session IDs last only as long as the human or search robot visitor is on the site.  Consequently, every time a search engine returns to re-index a page, the page will not be found since the URL containing a session ID is no longer valid.  This is important because the algorithms used by search engines to determine rankings to a keyword search are much more receptive to webpages where the content is associated with a stable URL.  In this way when the search engine lists the site in a keyword query clicking on the link will actually direct the search engine user to a working page.  This, of course, improves the search engine’s ability to satisfy its users.  For search engines rewarding sites having stable URLs is one way to ensure quality when delivering search results.  They know users do not want to be presented with a result to their search query that when clicked leads to a “page not found” message.

Obviously, web marketers that use session IDs to gain insight into site visitor activity must consider the cost/benefit of dropping session IDs in favor of potentially improved search engine traffic.  The good news is that search engines are improving their ability to recognize session IDs and strip these from a URL without affecting the link.  But this ability is still inconsistent and web marketers seeking improved search engine traffic are advised to consider removing session IDs from their site’s URLs.