Twitter decides if your tweets will be shared or de facto shadow banned, in part, on who follows you and who you follow:

Twitter, for example, now factors in the behavior of other accounts in a person’s network as a risk factor in judging whether a person’s tweets should be spread.

That means that the people who follow you – which you cannot control – are a factor in whether your tweets are shared with your followers or appear in searches.

Meanwhile, Facebook is algorithmically assigning every user a trustworthiness grade. How this score is determined is not known, but it takes into account how many times your posts have been flagged, and how many times you have flagged other posts as false – but which were actually true.

Facebook claims to use “thousands of behavioral clues” to calculate your score.

Bottom line: Both Facebook and Twitter are secretly judging each of us and assigning us a score. We have no way of knowing what is considered good or bad, as that is secret. We have no way to learn what our score is – nor any way to correct errors on the part of Facebook and Twitter.

Source: Facebook is rating the trustworthiness of its users on a scale from zero to 1 – The Washington Post

TechCrunch has much more on Facebook’s trustworthiness score – and how it is used to filter what items you see.

Facebook is acting as a pure publisher, selecting the content you see. They are no longer operating under the “safe harbor” provisions of acting like a phone company that is not responsible for the content on their platform. At this point, Facebook and Twitter are both curating the content you see, and how your own content is seen by others. Both are de facto publishers.