A product that is uniquely identifiable according to a globally unique identifier (GUID)(100) includes a class identifier (CID)(110) that uniquely identifies at least one product class in which the product is categorized (along with a plurality of other products) within a class hierarchy of a global content directory (42). The product class defines one or more attributes of the products categorized in the class. The product also includes a product identifier (PID)(120) that uniquely identifies the particular product from among the plurality of products categorized in the product class uniquely identified by the CID (110). The CID (110) and PID (120) collectively provide the GUID (100), which may be specified or determined to facilitate a commercial transaction involving the product.