I just got an email addressed to no less than 78 人, and all 78 people’s email addresses were in the To field. You’d think the sender would put all our emails in the Bcc field since, 良好, the recipients don’t really need to know the emails of the other 77 people who got the email. (In its defense, putting all the emails in the To field makes stalking easier, but isn’t that what Facebook’s for?)
I can understand why Cc isn’t that popular: it does the same thing as To, except it carries a different semantic meaning. Most teenagers (and a bunch of adults too) couldn’t care less about the fancy schmancy semantic meaning, so they just use To.