in "1984" the fake stories had one thing going for them. Once they were faked, all of the original stories or news items were obliterated including sometimes the people involved in the original story.
We haven't gone that far yet.

If they're serious, I expect to see most of the "mainstream" news sites disappear from social media.

"Don't look at that alternative news site. Just take part in our 2-minute hate..."
Fake news targets are emotion, and is more akin to a fit of hate for Emmanuel Goldstein. Actual facts are more boring.

It's easy to get fired up about something like how negligent BP engineers were to allow a spill. The work that extracts huge amounts of oil mostly without incident is the opposite of fake news.