Without human input as to what is correct and real of these inputs, its just another input that can be gamed.
A site's trustability could be punished when one of its fact checks is flagged for review and discovered to be wrong.
Will be interesting with Wikipedia in the mix. It could be the web's fact checking backbone.
Google mentions this in the docs, but if it's page ranking, that can be gamed, and if it's "pay us to be a fact checker", well...
Not ideal to leave Google in control of Truth (and they might not want the burden), so it'd be interesting to offload that responsibility to Wikipedia, which seems to have a pretty good system for coming to a consensus.
Fact checking doesn't automatically mean people will believe the fact checker over the top link anyways. Exposing people to disagreement to the issue from the start may be important because once people form a belief, they're much more likely to hold that believe despite contradictory evidence.
Incidentally, those who think ML would help need to take a look at the training corpus.