This is a substantial enhancement to the SMTP service. By simply setting your email client to use SMTP AUTH and passing in your JangoSMTP username and password, the system will be able to assign your emails to your account. This is especially beneficial to organizations that send emails from many different From Addresses through one single JangoSMTP account.
As a result, we will soon be taking away the screen within Settings where you would normally specify a list of From Addresses when using SMTP username/password authentication.
Note that this only applies to users using username/password to authenticate into the SMTP server. If you're using IP authentication, then there is no change, as users using IP authentication have always been able to send without specifying From Addresses.