Shown are some facts which are e-mail related, and therefore administred in a Mail::Internet object. Think for each Mail::Internet object as being one role which the user has when processing e-mail. For instance, I have a professional e-mail address, a work address, about 5 different webmaster and info addresses, and so on. For each role, I want other defaults to be affected: probably even different character sets to be used.

Mail::Identity is the very smart brother of Mail::Address, the most often used e-mail module. See also the other talk (same day, same conference) about Unicode MIME Headers which shows the very clear the benefit of the Mail::Identity class.