> Obviously given that large scale persuasion is now cheap and automatable - even in a representative democracy you might well choose to set the political weather by directly targeting the electorate.

In "the older days" even blatant propaganda used to work so well, because there were very few points of access to information and those could be easily controlled. Very few had access to independent sources of information and the rest relied on hearsay, at best.

The fact that you believe in this "it's different now" (under a thread about speech control on the internet) is a partial proof of how effective the propaganda had been up till now.