Credibility is earned by being consistently credible. A source that posts misleading or false articles can be assumed to not be credible, and I don’t trust them just like I don’t trust people who say stuff that ends up being not credible.

With newer information, concensus between difference sources us a good indicator as well.

What I am far more likely to use to dismiss something is checking out the purpose of the group. If they have a website and their description sounds like a weasel pretending to be a benevolent protector of a hen house then I just ignore them. Anything that sounds pie in the sky, like revolutionizing or disrupting an established industry is probably another Theranos and easily dismissed. If they say anything that sounds like conservative doublespeak, they get ignored.

It seems to be a pretty reliable system even if the occasional thing that is too good to be true slips in because I want it to be true. But having low expectations and recognizing potential being different from the results helpas a lot with being pleasantly surprised when things turn out better than they sounded.