Yahoo Mail had (has?) a feature that allowed you to set an alternative email address while keeping your original email address intact.
you could be first_last@yahoo.com but also have rando_waldo@yahoo.com or ymail.com receive emails in same mailbox. And you could choose the "From" address form a drop-down when sending outbound emails or replies.
you could be first_last@yahoo.com but also have rando_waldo@yahoo.com or ymail.com receive emails in same mailbox. And you could choose the "From" address form a drop-down when sending outbound emails or replies.