An e-mail alias is an email address which uses the very same mailbox along with the initial e-mail. For example, you could have email@example.com as your original e-mail address and create an alias firstname.lastname@example.org. Each of the addresses can share the same mailbox, so emails sent to either one of them shall be received in one place. Feel free to use aliases for various reasons, such as emailing various types of people or signing up on sites. Any time you begin to get a great deal of spam, for instance, you can just remove the alias whilst your original mailbox will not be impacted at all and you'll retain the emails that you need. Aliases in many cases are considered to be a substitute for forwarding emails from one email address to another if you are using 2 or more email address for contact on your web site.