A catch-all functionality that is activated for a specific e-mailbox will permit you to receive emails that are sent to email addresses that do not really exist. Otherwise stated, if you remove an email address and somebody still sends an email message to it, or to any mistyped email address under the very same domain name, you will receive the email in the catch-all mailbox. Using this functionality means that you will no longer miss an email for any reason whatsoever, which could be crucial if you run some business, for instance. Since you may start receiving spam emails, you can use the catch-all option with email filters in order to get only real messages in your inbox. Only one mailbox per domain can be a catch-all one and email forwarding cannot be set up for a catch-all mailbox.