Sure, the Obama and Clinton campaigns used social media and astroturfing. And they developed and targeted their stuff based on psychological profiling. However, as I understand it, their stuff was targeted only in traditional ways. Based on lists from various sources. Some of those lists were based on website signups, and even posting history and so on. But they generally weren't very granular.

Basically, Cambridge Analytica took the behaviorally targeted ad approach that's taken over the Internet, and applied it to political campaigns. So they're doing psychological profiling at the individual level. They targeted likely Clinton and Sanders voters with messages that discouraged voting. They targeted likely Trump voters with messages that bolstered support and encouraged voting. Messages in ads. In Facebook and Twitter posts by agents and bots. Telephone calls. Physical visits by canvassers, who carried phones with apps that provided real time access to individual user profiles.

That was new tech!

But of course, now everyone will be using it. If they can afford it, anyway. And what does that portend for democracy? Nothing good, I'd argue.