And confirmed that it really is an immediately doable discrete action, as opposed to a project, an idea for a project, a Waiting For, or some form of amorphous "stuff." If *all* you've done is move the item from one location to another, either you haven't really processed it or it was already processed when it went into your inbox. In most cases, the former is more likely.
Definitely. Further, *I* would not call any other list an inbox. An inbox is just something which can hold items coming in, letting them wait for you to decide what they mean to you. Action list is just that: list of actions.