A catch-all feature that is activated for a given email mailbox will allow you to receive emails that are sent to email addresses that do not really exist. To state it differently, if you deactivate an email address and somebody still sends an email to it, or to any mistyped email address under the same domain, you will get the email in the catch-all mailbox. Using this functionality implies that you will no longer miss an email for any reason whatsoever, which could be crucial in case you run a company, for example. Since you may begin receiving unsolicited messages, you can use the catch-all functionality with anti-spam filtering software in order to get only real emails in your inbox. Just one mailbox per domain can be a catch-all one and email forwarding cannot be activated for a catch-all mailbox.