OOH (Out-of-Home)

Out-of-home (OOH) advertising is the umbrella category for any commercial message placed outside the home, bus shelters, highway billboards, transit interiors, mall posters, gym lobbies, bar TVs. Digital OOH is the fastest-growing subcategory, but OOH as a whole still includes a long tail of analog inventory: paper posters, painted walls, static vinyl.

The OAAA, Out of Home Advertising Association of America, maintains the canonical US taxonomy: Billboards, Street Furniture, Transit, Place-Based, Cinema, and a catch-all "Alternative" category. Each has analog and digital variants. The IAB's Digital Out-of-Home Buyer's Guide aligns its taxonomy to the OAAA so a buyer can map a media plan across both worlds.

Measurement-wise, traditional OOH used the Geopath audited foot-traffic model, a per-panel impression estimate derived from mobile-location data, traffic counts, and visibility geometry. DOOH inherits Geopath where sensors aren't available and overrides it with sensor-counted impressions where they are. Trillboards screens emit a sensor-counted impression per playout, which is the buyer-grade signal, Geopath is the modeled fallback used by most non-sensor networks.

Global OOH spend crossed $40 B in 2026, and the digital share crossed 50% for the first time. The analog tail isn't going away, a beach billboard is still the cheapest impression per CPM in beach markets, but every new install is digital.