Can't you track who subscribes to the RSS feed, because of that polling you mentioned. RSS is trivial to monetize, there are other reasons why Google/FB killed

Can't you track who subscribes to the RSS feed, because of that polling you mentioned. RSS is trivial to monetize, there are other reasons why Google/FB killed it such has having to educate people first, or not wanting to promote a free standard that would have not allowed them to monopolize the market