One of the reasons that Google has become the predominant search engine is their discovery and application of "PageRank" to search results. Google determines which search results are most relevant, in part, by examining hyperlinks in web pages.

The idea goes, if something is linked to, it implies trust. The more people who link to you, the more trust you must have, so links that you make to others have more value than other pages who don't have as many trusted links.

If that hurts your head a little, it should, because it's a recursive algorithm that constantly needs to be recomputed.

The problem with Facebook and most other social networks, is that they haven't applied the learnings from PageRank to their social networks. The news and information that gets surfaced shouldn't be based on what you most like, it shouldn't be based on ad revenue, or on other social network signals that are easy to fake.

Ebay has had a similar system for their sellers. To become trusted, you have to complete transactions that people say were legitimate. Uber and Lyft have it for their drivers (and riders). Facebook merely needs to provide a feedback loop (like "Likes", perhaps call them "Kudos" or "Rep") based on accuracy or other measures of veracity, and when articles with sufficient Kudos are shared, articles from those authors/sources are boosted. On the other hand, when authors or news sources have to publish corrections, are refuted by more trusted sources, or are found to have misled or lied, their ratings should drop, and they should unceremoniously be dropped from the "shareable" web-sphere.