I think Facebook may already have done the first one. That's probably not going to stop someone like Trump, though; his campaign staff mainly seem to see clever

I think Facebook may already have done the first one. That's probably not going to stop someone like Trump, though; his campaign staff mainly seem to see clever targetting techniques in terms of cost optimisation, as a way of not wasting money on showing people messages that are less likely to convince them. If people want to spread the other ads for free, that just saves them some money. It's not even clear that sleazy tricks with microtargeting are actually a winning strategy; people really don't like finding out they're being tricked and social media is pretty optimized for spreading that kind of discovery.