"Tracking the source of a new insight from a board/subreddit like that and over the weeks seeing it bleed into other sites, then eventually into real life news

"Tracking the source of a new insight from a board/subreddit like that and over the weeks seeing it bleed into other sites, then eventually into real life news programs and so on can be super interesting." Like injecting a tracer into the blood and seeing how it flows through the system -- that does sound super fascinating. Have you ever actually done it? I'm trying to think of how in practice you'd go about it, given how much noise there is for any signal. Any more specific tips would be welcomed.