or an i-number to an XRDS document describing the target resource. XRIs are backward-compatible with the DNS and IP addressing systems, so it is possible for domain names and IP addresses to be used as i-names (or, in rare cases, as i-numbers). Like DNS names, XRIs can also be "delegated", i.e., nested multiple levels deep, just like the directory names on a local computer file system. For example, a company can register a top-level (global) i-name for itself and then assign second- or lower-level (community) i-names to its divisions, employees, etc. Examples: =Mary.Jones*Henry @Example.Corp*Ecuador*Quito i-names are called unified digital addresses because they can be resolved using the XRI resolution protocol into XRDS documents that expose various services for accessing the digital identity they represent. These services, such as OpenID, OAuth, or XDI can expose any other type of data under the control of this identity. Privacy is protected because the identity owner controls access. For example, the registrant of =Mary.Jones would not receive spam from this i-name because it is not an email address. To resolve =Mary.Jones into an email address would first require Mary's permission, and such requests can be verified by i-brokers to make sure they are legitimate. In addition to =names for people and @names for organizations, the third major type of i-names is +names for generic concepts. This is the XRI equivalent of a generic noun in the English language, for example, +flowers, +phone.number, or +table.of.contents. Generic +names are very useful in distributed data sharing because they can be used as XRI cross-references to specify the precise type of data to be shared. For example, =Mary.Jones/(+phone.number)/(+daytime) and @Acme/(+phone.number)/(+daytime) can be used to request Mary's and Acme's daytime phone numbers, respectively. See also Global context registries I-number XRI (Extensible Resource Identifier) XRDS (Extensible Resource Descriptor Sequence) XDI (XRI Data Interchange) Social Web Zooko's triangle References External links OASIS XRI Technical Committee OASIS XDI Technical Committee XDI.org XDI.org Global Services Specifications for public i-name registry services. XDI.org I-Services Specifications for public XRDS identity services. The Social Web: Creating An Open Social Network with XDI in the Planetwork Journal. Identifiers