The poster. It used to be that shares/retweets were used to put a post on your friends feed and likes were used to express support/appreciation to the poster/creator.

Twitter always had the problem where faves (now likes) were public but people didn't always realize – they were used as a combo of bookmarks and upvotes. But even then, there was a difference between having your likes viewable on your profile and when they started randomly showing your likes on followers' feeds.