Because of the nature of a URI, it can be dereferenced to get the information of the thing it represents—hence the term dereferenceable URI. SSN and a person's name are not dereferenceable because, even though you could search for these strings on the Web, it is not guaranteed that the information exists and is unambiguous. In other words, there is no canonical way of dereferencing those identifiers. On the other hand, URIs can be dereferenced by standardized protocols such as HTTP. Dereferenceable URIs are based on the well-established theory and practices of "data access by reference". A data access and manipulation mechanism is used extensively in general computer programming (e.g., C/C++ pointers) and database call level interfaces (e.g., ODBC and JDBC) amongst others. The term: dereferencing describes the act of obtaining a representation of a description of an entity via its URI.