Social media sites allow users to share and access news and information but how it shares information depends on how you interact with the members of your network.
All social media platforms have an algorithm, basic computer programming or logic, that helps to sift through all the content generated by the people the user is friends with or follows.
The news feed works on the principle that what you interact with is a key indication of what you want to see. It also takes into account what others like and whether the information is recent or is considered to have high importance, like someone getting married. But it can also mean that you may not see other interesting content because others are not interested or you have not interacted with that other user recently.