Why not? On most major hosts it has a special meaning, and otherwise it is a relatively ridiculous thing to just add willy-nilly to your email address. We keep your verified mailbox address, the one you gave us, for sending mail.
I doubt we'll ever turn away a customer by preventing registration of a new account sharing the prefix to a plus sign in their email address with an existing customer.
I doubt we'll ever turn away a customer by preventing registration of a new account sharing the prefix to a plus sign in their email address with an existing customer.