I think it started, in internet form, when Clinton took office. It think it was a creation of Hillary’s War Room.
You're right. I remember the Clinton administration putting out a "report" showing (with flowcharts) how the right-wing purports to make news by first seeding outlier sites with stories, and then having those stories picked up by the networks, thereby putting the "news" into the mainstream without the MSM dirtying themselves by reporting the stories first.
Of course, this was the typical liberal behavior of projecting onto the Right what they themselves are doing.
I wish I can find that report, but I'm not using the right search terms.
-PJ