Twitter has updated the definition of “What’s a Twitter timeline?” in its Help Center, specifically adding this point:
Additionally, when we identify a Tweet, an account to follow, or other content that’s popular or relevant, we may add it to your timeline. This means you will sometimes see Tweets from accounts you don’t follow. We select each Tweet using a variety of signals, including how popular it is and how people in your network are interacting with it. Our goal is to make your home timeline even more relevant and interesting.
These changes are not implemented yet, and we have no information how and when they are going to happen. However, it seems like Twitter is becoming more like Facebook.
One thing I can say for sure: Twitter has been the place where I used to see what I wanted to see.
So, hopefully a Tweet, an account to follow, or other content that’s popular or relevant will be really what I want to see.