The Contact Object Protocol serves as the basic organizational unit for the personal information of a user's associates and acquaintances. This protocol also serves as the basic organizational unit for lists of e-mail addresses.
Sections 1.8, 2, and 3 of this specification are normative and can contain the terms MAY, SHOULD, MUST, MUST NOT, and SHOULD NOT as defined in RFC 2119. Sections 1.5 and 1.9 are also normative but cannot contain those terms. All other sections and examples in this specification are informative.