I remember the last time you brought this up way back when, and I was in agreement with you then. I like that you've refined your idea since then, and I am 100% onboard with it now as well. Advertising can be done via the blockchain the way you described with minimal re-tooling and minimal additional programming, since it uses functions that already exist. It just requires some novel implementation.
Upvoted 100% and resteemed. I want to get this idea circulated some more. Hopefully the devs can see this and give it some thought.