[soared]

Charity billboards are likely PSAs that brands use to test the effectiveness of a billboard. You find two very similar towns, each with a walmart. Buy a billboard in each town, but in town A put up a walmart ad, in town B put up a charity/PSA billboard. Over simplifying, but if sales in town A increase more than town B then the billboard is effective.

[rossdavidh]

Interesting possibility, but wouldn't it be cheaper to just not buy any billboard ads in that town?

[soared]

I honestly don’t know. I’ve only read about this type of testing and a friend does it for direct mail at work but I’ve never used it. I think in digital or direct mail that you have the ability to track those users, which I guess doesn’t apply with billboards.