Earlier this month Twitter tested a new feature that shows tweets into users timeline from accounts their friends follow. This experiment was not accepted by many users, however, it looks like Twitter has made this experiment official.
The micro blogging site has officially announced that users will indeed see trending and popular tweets from people they do not on follow on their timeline. Twitter has acknowledged the change by updating the Support Page on its website. This policy change was first spotted by Quartz.
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.
read the Support Page titled What’s a Twitter timeline?
This update will not give Twitter users any control over their timeline similar to the ads and retweets. The new move is aimed at making it easier for people to discover new people or brands to follow. However, many users might frown upon this action from Twitter as it pollutes your timeline with content that is not relevant to you.