To specify an email address that is used to identify or contact an organizer or attendee.
This property parameter is defined by the following notation:
emailparam = "EMAIL" "=" param-value
This property parameter MAY be specified on "ORGANIZER" or "ATTENDEE" properties. This property can be used in situations where the calendar user address value of the "ORGANIZER" and "ATTENDEE" properties is not likely to be an identifier that recipients of scheduling messages could use to match the calendar user with, for example, an address book entry. The value of this property is an email address that can easily be matched by recipients. Recipients can also use this value as an alternative means of contacting the calendar user via email. If a recipient's calendar user agent allows the recipient to save contact information based on the "ORGANIZER" or "ATTENDEE" properties, those calendar user agents SHOULD use any "EMAIL" property parameter value for the email address of the contact over any mailto: calendar user address specified as the value of the property. Calendar user agents SHOULD NOT include an "EMAIL" property parameter when its value matches the calendar user address specified as the value of the property.
ATTENDEE;CN=Cyrus Daboo;EMAILfirstname.lastname@example.org:mailto:opaque-toke email@example.com