And the Facebook UI really hates conversations. There are only 1-deep threads, if a post has hundreds of replies you see maybe 5 (Facebook will say they're the "Most relevant" because probably the amount of Likes) and you have to click "Load more comments" dozens of times to try to read all the responses. Add to that people just commenting with their friends' names (tagging them) to notify those friends about the conversation, because they don't know about the "copy link" or "Share this comment" features...