A feature I recently used in working on ISC internal applications is the ability to send emails on behalf of someone. This is useful when generating system notifications from an application when you want some of them to show up as being from a specific person, perhaps posting comments on a work ticket.

In my case I was updating our facilities work order system for tracking requests. Normally all notification emails are sent from the same noreply email address. I wanted to change that so comments added from the original requester would show up as being from them and stand out.