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 email 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 [RFC2119]. Sections 1.5 and 1.9 are also normative but do not contain those terms. All other sections and examples in this specification are informative.