The difference I see is that there is feedback on the ads other than sales and it seems like you could closely tailor ads to specific demographics.
I think this is the risk we pay by reading the Internet? The filtering implicit in things going viral is a mixed bag.
Imagine a billboard, you drive and the content changes because your GPS is close to that billboard and stuff like that - real world changes like that will happen, if not already.
There is also the product placement and as Cambridge Analytica describes entire personas and website being made just to target individuals and change their perception and opinions - this can all be automated at scale with current technology.
Or your Google self-driving car just happens to pick a route past certain billboards and retailers...