The short definition
Digital out-of-home (DOOH) advertising is any advertising displayed on a digital screen located in a public or commercial space — as opposed to advertising on someone's personal phone, laptop or TV at home.
That includes large outdoor displays, transit screens, and the growing category of in-venue screens inside the businesses people visit throughout the day: waiting rooms, dealerships, restaurants, gyms, retail floors and more.
How it differs from traditional out-of-home
Traditional out-of-home — printed billboards, posters and signs — is static and fixed until it's physically replaced. DOOH uses digital screens, so the same surface can run video, rotate multiple messages, be scheduled by time of day, and be updated remotely.
That flexibility is why DOOH has grown quickly: advertisers get the real-world presence of out-of-home with much of the control and creative range of digital.
Why brands use it
People spend a large share of their waking hours away from home, in physical places where personal-device advertising can't easily follow them. DOOH reaches audiences in those real-world moments — often when they're relaxed, waiting, or actively making decisions.
Because in-venue screens play full-screen content in captive settings, video-first DOOH can hold attention in a way that a scrollable, skippable feed often can't.