What is geofencing?
Geofencing is a location-based advertising tactic that sets a virtual perimeter around a physical place, such as a store, stadium or neighborhood. When a mobile device is detected inside that boundary, it becomes eligible to see ads, either right away or later. It helps brands reach people based on where they are or where they have been.
Geofences can be as large as a district or as small as a single building, though very small fences depend on precise location data that is not always available.
How geofencing works
Draw the fence: the buyer sets a radius around an address or coordinate, or draws a custom shape on a map.
Read location signals: bid requests can include device location. The most precise signal is GPS latitude and longitude from apps where the user has granted location permission. IP addresses also give a location, but usually only at city or region level.
Match and bid: the DSP compares the device location with the fence and bids when it matches.
Build audiences: devices seen inside a fence can be saved as an audience segment and targeted later, for example people who visited a trade show last week.
Because precise location mainly comes from mobile apps, geofencing works best with in-app advertising. Web inventory usually offers less exact location.
Common uses
Driving visits to nearby stores or branches.
Reaching attendees at events, venues or campuses.
Conquesting, which means targeting people near a competitor's locations.
Supporting store openings or local promotions in a defined area.
Following up with past visitors through retargeting.
Why geofencing matters
Location is a strong signal of intent and context. Someone near your store can act on an offer today. Geofencing also lets local and multi-location businesses keep spend close to where they can actually serve customers, instead of paying for impressions in areas they cannot reach.
The tradeoffs are scale and accuracy. Small fences can produce very few impressions, and location data is not always exact, so results need to be checked against real outcomes.
Privacy rules
Precise location is sensitive data. In Europe, GDPR requires a valid legal basis, usually consent. Several US states have privacy laws that treat precise location as sensitive, and some restrict geofencing around health care facilities. Most platforms also bar targeting around sensitive places such as clinics or places of worship.
Geofencing vs geotargeting
Geotargeting uses standard areas like countries, regions, cities or postal codes. Geofencing uses a custom boundary, usually much smaller and built around a specific place. Geotargeting is the default for most campaigns. Geofencing is a narrower tool for local, event or visit-driven goals. Many campaigns use both, with geotargeting for broad coverage and geofences around key locations.
Geofencing with AdGeeks
DV360 supports location targeting down to a radius around an address, and in-app inventory provides the most precise signals. AdGeeks traders set up location campaigns, check that fences have enough scale and can pair them with digital out-of-home screens in the same area.
