How does one guard against fake news on Facebook and in other media? Time cures a lot of things. I find that waiting a while, or even a few days, when I see a news story helps. With time, the false stories usually fall by the wayside as people do fact checking and so forth. Breaking news interests me less than the long term issues. This may not be the total solution to the fake news problem, but it's one strategy that can help. Wait, take the long view. Don't necessarily re post right away. Let fact checking take its time.
This can be a strategy for media consumers (readers), but it also might work for companies like Facebook that are looking for algorithms to combat fake news. How does one design an algorithm that's not got its own built in biases? Well, the march of time gives no preference to anyone. Time can be considered when articles are highlighted. In other words media shouldn't be too "trigger happy" to get the scoop. I know that kind of patience might not be the best business model, however.
I read that companies, like Facebook, are considering having a tag to certify that certain stories have been verified. A good idea tho there is still the question of who decides what to tag and what is the process to decide this? One thing that any process, like that, would do is slow down the news a bit. It takes time to verify and process stories for placing the "verified" stamp on the item. Of course all postings would still go onto Facebook as they do now, but certain things would have the verified tag. Since there would likely be a wait for news items to go through whatever process created the tag, this might automatically favor the longer term "slower" news over the "breaking" news anyway.