A method, system, and computer-readable medium is described that provides one or more types of services and/or information in response to an information request or other message that specifies a unique identifier of a defined type. The information requests can include requests for resources corresponding to specified URLs with domain names that include a unique identifier, and if so the service or information provided can be based on the defined type of the identifier and/or on an item corresponding to the unique identifier. Additional information included in header fields of HTTP messages used for such URL requests can also be used to determine services or information to be provided, either instead of or in addition to the specified domain name identifier. In addition, services and information can be provided for a requested URL that includes a domain name that has not been explicitly registered with the DNS name server computers.