If you've ever passed a digital billboard cycling through ads, waited under a screen at a bus shelter, or glanced at a TV above the bar, you've already met DOOH. Digital out-of-home advertising — DOOH for short — is advertising on the internet-connected screens that live in the physical world, outside the home and off your phone.
For decades these screens were the exclusive turf of national brands with six-figure budgets and long lead times. That's the part that's changing. Here's what DOOH actually is, how a screen gets bought, and why a local business can now run the same kind of campaign a global brand does.
What counts as DOOH?
DOOH covers any digital screen in a public or shared space that can display a paid ad. In practice that includes:
- Roadside and large-format digital billboards along highways and busy streets
- Transit screens in subways, bus shelters, airports, and train stations
- In-venue TVs in bars, gyms, salons, waiting rooms, and convenience stores
- Place-based networks in malls, office lobbies, and parking structures
- Street-level "urban panels" on sidewalks in dense neighborhoods
The common thread is that the screen is digital — so the ad can be swapped instantly, scheduled by time of day, and changed remotely. That's the leap from a printed vinyl billboard, which stays put for weeks no matter who's walking by.
DOOH vs. traditional out-of-home
Traditional out-of-home (OOH) — painted walls, posters, static billboards — is still a large part of the market. But the industry is going digital fast. Grand View Research values the global DOOH market at roughly $23 billion, growing toward $39 billion by 2030, and eMarketer expects digital to make up a growing majority of out-of-home dollars before the decade is out.
The reason is simple: digital screens are flexible. A static billboard sells one message for a month. A digital one can run a coffee promo at 7am, a lunch special at noon, and a happy-hour offer at 5pm — to different audiences, measured along the way.
How a DOOH screen gets bought
There are two ways to buy:
- Directly from the company that owns the screens (a "media owner"), usually with a contract and a media planner.
- Programmatically — through software that buys screen time automatically, the same way digital display and social ads are bought. This is the modern path, and it's what makes small, flexible budgets possible. We cover it in programmatic DOOH, explained.
Programmatic buying is the unlock. Instead of negotiating a month on one billboard, you set a budget, a location, and a goal — and software places your ad across many screens, only where and when it makes sense.
What can you measure?
A fair question about real-world screens is: does it work, and how would you know? Modern DOOH offers more measurement than most people expect:
- Impressions — modeled from anonymized mobility and traffic data (how many people realistically saw the screen)
- Footfall lift — whether exposure drove more visits to your location
- QR scans and short links — a direct bridge from the screen to a phone action
- Geo-lift studies — comparing areas that saw your ad to areas that didn't
It's not the click-by-click world of search ads, but it's a long way from "spray and pray."
Why DOOH is having a moment
Three things are converging. Screens are now everywhere and connected. Programmatic buying removed the minimums and the lead times. And advertisers are looking for attention they can't be scrolled past, ad-blocked, or skipped — which is exactly what a screen in the real world delivers.
That's the shift Glo is built on. DOOH first, CTV also: start on the screens of real life, and extend the same campaign to the living room. One good video becomes reach you can point at a single block or a whole country — self-serve, from $29/day, no contract.
If you're weighing where your next ad dollar should go, see DOOH vs. CTV vs. social, or jump straight to how much DOOH and CTV actually cost.