of messages in context to a given discussion topic more time efficient and with less mental effort, thus making more time and mental resources available to further extend and advance discussions within each individual topic/thread. In group forums, allowing users to reply to threads will reduce the number of new posts shown in the list. Some clients allow operations on entire threads of messages. For example, the text-based newsreader nn has a "kill" function which automatically deletes incoming messages based on the rules set up by the user matching the message's subject or author. This can dramatically reduce the number of messages one has to manually check and delete. Real time feedback When an author, usually a journalist, posts threads via Twitter, users are able to respond to each 140- or 280-character tweet in the thread, often before the author posts the next message. This allows the author the option of including the feedback as part of subsequent messages. Disadvantages Reliability Accurate threading of messages requires the email software to identify messages that are replies to other messages. Some algorithms used for this purpose can be unreliable. For example, email clients that use the subject line to relate messages can be fooled by two unrelated messages that happen to have the same subject line. Modern email clients use unique identifiers in email headers to locate the parent and root message in the hierarchy. When non-compliant clients participate in discussions, they can confuse message threading as it depends on all clients respecting these optional mail standards when composing replies to messages. Individual message control Messages within a thread do not always provide the user with the same options as individual messages. For example, it may not be possible to move, star, reply to, archive, or delete individual messages that are contained within a thread. The lack of individual message control can prevent messaging systems from being used as to-do lists (a common function of email folders). Individual messages that contain information relevant to a to-do item can easily get lost in a long thread of messages. Parallel Discussions With conversational threading, it is much easier to reply to individual messages that are not the most recent message in the thread. As a result, multiple threads of discussions often occur in parallel. Following, revisiting, and participating in parallel discussions at the same time can be mentally challenging. Following parallel discussions can be