This article was published just before the election, but it nicely summarizes the Russian use of propaganda in the US, and how sites like zerohedge knowingly or otherwise propagate it. One of the authors, Clint Watts, testified at the Senate hearings last week.

https://warontherocks.com/2016/11/trolling-for-trump-how-russia-is-trying-to-destroy-our-democracy/

One simple chain, for example, would be Putin > RT.com > zerohedge > Fox News > Trump> Trump fans > G&M comment pages