I'm adding my opinion to this thread after a little bit of back-and- forth with @simX and @KuraFire on Twitter the other day. 140 characters is just not enough to convey a complete argument.
This change of functionality has turned a feature that was in a definite gray area, to black and white. The application is no longer assuming a user's intentions (possibly incorrectly), but requiring them to assign the additional data if they wish. Yes, it takes additional effort to create additional information, but saving and displaying assumed-to-be-correct information as fact is wrong. When you create a new message in Apple Mail (or any other mainstream mail client I'm aware of) it is not automatically marked as a reply to the last message you received. You have to specify which message you are replying to, and have the choice to start a new thread by replying to nothing at all. Your solution does not provide this as an option. All messages prefixed by a username will be treated like a reply with no way to opt-out. Your suggestion to include multiple posts on all an individual status pages is conventionally incorrect. A direct link should only show one status: the one you asked for. However, Twitter could take advantage of the 100% accurate metadata present in the new reply functionality and create conversation pages showing the thread. This, and any other application taking advantage of the metadata, would be broken if it contained the false positives your solution introduces. Travis Dent @tcdent