Allow other identification techniques than simply name
Add a section 3.2.4:
3.2.4 "atom:host" Element
The "atom:host" element's content conveys an IP address associated with the Person construct. Person constructs MAY contain an atom:ipaddr element, but MUST NOT contain more than one. Its content MUST be a domain name [RFC1035] or a dotted-decimal IPv4 address or a colon-delimited IPv6 address.
In prior versions of the specs, at least one child element was required. This requirement disappeared, but I am not certain why. Does it make sense to have a person element with no children? - SamRuby