I thought I remembered it being called "submarining" but that seems to be something else. I also thought I remembered Joel Spolsky writing about it but can't find it now.
Other than those, it was literally Medium and social media.
What you can do is write a polished opinion piece and tell one of your assets, or pay some politician, to publish it as an OpEd in outlets like the WaPo and NYT. Or you can get nobodies who know nothing to publish similar articles to each other in Wired, the International Business Times, and Forbes (either by "leaking" to them or because they're on your payroll), then get politicians to mention those articles in Congress and to write furious letters to WaPo and NYT accusing them of covering this story up - and then they'll write your propaganda themselves.