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.