What is an Information Radiator?
An information radiator is a large, always-visible display of project truth — task board, burndown, build status, CFD — placed where people can absorb it in passing, no login, no meeting, no asking. The term is Alistair Cockburn's: information should radiate into the room.
Its opposite is the information refrigerator: data locked in a tool nobody opens. Radiators build trust through transparency — including with the stakeholders you'd rather not surprise.
Worked example
A team mounts a monitor by the coffee machine: sprint board, build status (red/green), and the burndown. The department head stops booking "quick status calls" — he walks past the truth twice a day. When the build goes red at 14:00, three people see it before the alert email is even opened. That ambient awareness is the radiator working.