If a user opts not to use Yahoo!, he or she will have to set up POP in a desktop email program to access the email address. Although the user isn't using Yahoo!, you're still responsible for anyone using an email address associated with your domain.

If any of your email users violate the Yahoo! Terms of Service in conjunction with a Business Mail plan, Yahoo! reserves the right to suspend your domain and deactivate any email addresses associated with it. In light of this, when you accept the Terms of Service again, you're acknowledging that you understand your responsibilities for the POP-only email account.