[eh_why_not]

Good point and a real concern. I considered an analogy to the physical world and used that: if you are a local business and want people to know about your product, you can rent a billboard in the town square, or buy a spot on a local TV channel.

The idea is that as long as it is coarse-grained geography it was less damaging.

But would that make it dangerous for political and ideological mass "influencing"? Maybe you're right. If we ever get a chance to have laws and regulate it, maybe allowing certain categories only.