Just the other day I saw someone asking how and why does Facebook choose whose posts they see on their newsfeed. They were confused how they sometimes kept seeing the same stuff day after day and then all of a sudden someone's post just leapt on their feed. I have actually wrote around this subject in a couple of times. I've told you why how Facebook brings out the narcissistic side in all of us. I've also wrote about how many people see your posts on Fb. Recently I gave a couple of tested and working methods for boosting your Facebook page reach. But I've never quite directly explained why you see that certain pal's posts on your feed.
The foremost thing I've mentioned on all of those articles apply: When you engage with one or more posts by someone on Facebook, post on their timeline or even visit their profile enough you will start to see more and more of their posts on your newsfeed. Also you may notice that your new friends' posts will be featured on your timeline for a while, unless you keep ignoring them. So more you like or comment a Facebook friend's (or a page's) posts, the more you keep seeing other posts by them.
But then there's a twist. That part where suddenly someone's post appears to your feed, even though you haven't really engaged with their content. Or when old posts make a reappearance after a couple of days. You may notice that those posts have gained more than usual comments or likes, thus Facebook believes you must also be interested about this stuff. Besides your own engagement Facebook also looks at the overall engagement when deciding what you should see. Additionally boosted posts and ads are more likely to show on your newsfeed since that's how Facebook makes money. Then there seems to be this sort of a "hey, you haven't been in touch with this person for a while". They show up like suggestions of who you might have missed and would like to say hi. Those usually happen with someone who hasn't posted on Facebook recently and then comes back posting something.
The catch is in the title of this article. Facebook newsfeed shows you what you should see. At least this is what their algorithm decides you should see. It's not necessarily what you want to see nor it's necessarily what would be good for you to see. There's no army of elves who check each post and choose the best stuff for you. There's only loads of code and tons of calculations which make the assessment based on different things, such as your previous interests and how well a post is doing amongst other's who already saw it.
This actually applies to more than Facebook. As an example Google's search works with the same logic. Your previous interests and an overall popularity of a content makes it more likely to show up on your searches. Oh yeah, search results aren't the same for all of us. Of course these are only a couple of the variables that makes you the choices on your Facebook newsfeed or your Google searches. They are like a mother who's choosing the clothing for their child. The child has a say, but their say is very limited and often is not listened thoroughly. They are not telling what you want or need, they are telling what you should.