author — Gives name and contact information for originating party of the associated data
name- the name of the author or last modifier of the associated element's data
org- the author's organization
xns(optional) - the eXtensible Name Service identifier for the author [Deprecated]
email(optional) - the e-mail address for the primary author [Deprecated]
author includes alternate means of identifying author using XNS or normal e-mail/address. The address subelement is to be replaced with the more complete contactInfo subelement.
Both the xns and email attributes are deprecated and will be removed. XNS was a proposed internet technology (eXtensible Name Service) to reduce spam that didn't catch on. It is replaced with the 'iname' subelement as a single means to identify an individual or corporation in lieu of typical (and quickly dated) e-mail, phone, or address information. The author element itself is deprecated and should be replaced with the contactInfo element