[Mashimo]

Interesting. Where are billboards on private property common?

I mostly see them on tv, public billboards and light poles.

[Aardwolf]

Here's an example: https://img.nieuwsblad.be/vXdqo10D824EJ6p5Ab4IBfARaZs=/960x6...

[hsbauauvhabzb]

Australia small signs (100cmx50cm size) are common. Billboards you’d see down a commercial street are probably private property and often are political also.