This is discussed to death in other threads on the board, but, very very briefly, WDW's new policy is there is no more Do Not Disturb hanger for your door. It was replaced by a Room Occupied hanger. The difference is that now, if you haven't had housekeeping for 24 hours, they will send someone to your room to check on it/you. But if you have had housekeeping--as I found out from the CM who telephoned me earlier this afternoon--then no one else will bother you.
If you turn down housekeeping, this could be a problem, but if, like me, you always get housekeeping, I think it's a nonissue.