You've probably noticed it without naming it: a screen above the counter at your gym rotating through ads. A display in a waiting room. A digital menu board that occasionally shows something other than the menu.

That's indoor DOOH — digital out-of-home advertising — and it's shown up in more places over the past few years for a reason that has nothing to do with trend-chasing. It solved a real problem: traditional billboard advertising has priced most small businesses out entirely, and DOOH is the format that actually let local advertising dollars back into places a small business can afford.

A standard highway billboard in most markets runs into the thousands of dollars a month before production costs, minimum commitment periods that can run months at a time, and it goes to an audience defined only by "everyone who drives past," which for most local businesses is mostly people who will never be a customer.

That math never worked for a business with a modest local marketing budget. It was built for regional and national brands, and it stayed that way for decades.

Indoor DOOH is a genuinely different format, not just a cheaper version of the same thing. Screens go inside specific venues — gyms, medical offices, restaurants, waiting rooms, breakrooms — places where the audience is already captive, often with real dwell time (waiting for an appointment, resting between sets, waiting for a table). That's a fundamentally different value proposition than a highway billboard glimpsed at 65 miles per hour: fewer total impressions, but each one happens in a context where the person isn't going anywhere for a few minutes.

This isn't a niche format anymore. According to the Out of Home Advertising Association of America (OAAA), the trade association that tracks industry-wide revenue, out-of-home advertising reached a record $9.46 billion in the U.S. in 2025 — its 19th consecutive quarter of growth. Digital out-of-home specifically accounted for 36.3% of that total revenue and grew 10.5% year-over-year, meaningfully outpacing traditional (static) formats.

I looked at several additional "global DOOH market size" figures from various market-research firms, and they range enormously — anywhere from roughly $20 billion to $35 billion for the same year, depending on which firm's methodology and geographic scope you use. That inconsistency is exactly why I'm not citing a single global number as fact. The OAAA's U.S. industry revenue figure is the one I trust, because it's a trade association reporting on its own industry's actual measured revenue, not a market-sizing forecast.

I wouldn't treat DOOH as a replacement for the fundamentals — a business that isn't showing up on Google yet has no business buying awareness advertising before fixing that. But for a business that's already handled the free stuff (see Issue #1) and has budget left for paid visibility, DOOH is worth a real look, for a few specific reasons.

Unlike a highway billboard, indoor DOOH is typically sold by venue, by screen, or by network — meaning a business can buy placement in a handful of relevant local venues instead of an entire market's worth of exposure it doesn't need.

A screen in a waiting room isn't competing with someone's phone the way a highway billboard competes with the road ahead. Dwell time matters, and it's part of why this format has grown even as attention has fragmented elsewhere.

The same discipline from Issue #2 applies here: ask what's actually being reported — plays, estimated impressions, dwell time data if the network has it — rather than accepting a vague promise that "people will see it."

Indoor DOOH exists because traditional outdoor advertising priced small businesses out for decades, and this format found a way back in — smaller audiences, but with real attention and real dwell time behind each one. It's not automatically the right next step for every business, but it's no longer a novelty either.

If this was useful, forward it to a business owner who's noticed these screens around town and wondered what they actually cost.

Curious whether indoor DOOH fits your business? See GSL Media's Indoor Digital Billboard Advertising service ⬇️