A universal resource indicator (URI), which includes a universal resource locator (URL), can be used to identify the name and/or location of a resource (e.g., a webpage) on a network, such as the Internet. In some URI's, besides information regarding the name and location of a resource, one or more parameters are present. When the URI is used to make a request for the resource, values of these parameters may determine one or more attributes of the resource that is provided in response to the request.