URL Parameters are tracking codes that you can use to track your keywords, and ads in your own personal CRM, or other databases. To use a URL Parameter, append it to the end of your keyword landing page URLs.
You can use the following types of parameters:
Engine-specific dynamic parameters (such as Adwords Value Track or Bing dynamic parameters).
Static parameters that refer to your own marketing campaigns, product codes, or other internal tracking information that you want to add to the landing page.