Google has added a feature to strip parameters from URLs to its Webmaster Tools. With extra parameters, search engines can index the same content under multiple URLs, which may split link equity.
Seven months ago, Google, Yahoo and Microsoft (at the time) signed on to create a canonical URL tag, to indicate what URL is the “correct” version, without parameters (although Google is the only one actively using this tag, for now). While that will also continue to work, this new one is probably better because the canonical URL tag requires the page to be crawled before it can be indexed, and might thus cost a little in initial crawl efficiency, but for most cases, it will probably be the easiest to implement and most universal solution.
To use this new feature, sign-in to your Google Webmaster Tools account, go to Site Configuration > Settings and click on the Adjust parameter settings »
