It would work like facebooks. It would show you who has seen your messages in your faction. This would only be able to be seen by founders, and they can give permission to officer so they can see it too. It would say the day that they've seen it aswell.
King Helios -> RE: Notebot "Seen by" feature (11/23/2012 11:17:58)
As a founder, Supported.
You could always ask them to say, "I have read this", on HQ notes.
If everyone in the faction does that, the message gets knocked off because there isnt a scroll bar. Some members might not be able to see the full message.