A catch-all feature that is activated for a given e-mailbox will allow you to receive emails that are sent to addresses that do not actually exist. Otherwise stated, if you deactivate an email address and somebody still sends a message to it, or to any miswritten email address under the exact same domain name, you will get the message in the catch-all mailbox. Using this functionality means that you will no longer miss an email for any reason, which could be essential in case you run a business, for instance. Since you may start receiving spam, you can use the catch-all feature with email filters so as to receive only real email messages in your inbox. Just one mailbox per domain can be a catch-all one and email forwarding cannot be set up for a catch-all mailbox.