this isn't getting localised in the user's language, BTW. we are now storing the user's language in the database. you can [activate the user's locale](https://github.com/mozilla/zamboni/blob/master/apps/users/models.py#L486) so the strings are localised properly for each email.

what my suggestion would be is to email each author individually like so:

    for author in set(product.authors.all()):
        author.activate_lang()
        subject = _(u'...')
        send_mail_jinja(...)