Door hangers, as the name suggests, are designed to hang on the door knob of your door. They are used by Real Estate agents and door-to-door salespeople to advertise their services.
The usage of the door hangers is not just limited to door-to-door salesmen and couriers. Some innovative uses of Door Hangers include:
Car rear-view mirror advertisements (for car dealerships and rental companies)
Hotel “do not disturb” signs
Hotel room service menus