It's a workflow function. So, you would change the state of a document from, say, Draft to Submitted for Review. And that change in state would trigger a set of (custom) events. So, maybe I set it up so that when the state is changed to "Submitted for Review," the file is now read-only except by the PM, and an email is sent to all team members, and all the files in the set are versioned. Then, maybe the PM changes the state to "Needs revisions" and that sets it back to writable and sends an email to the last person to edit it. We haven't implemented workflows yet, so I'm not 100% on what all is possible. But the challenge is that it's all customizable, so what "Approved" does in MY environment is likely different from what "Approved" does in yours.
-John J. Rauch, P.E.