A hierarchical to-reply list embedded in E-mail
There's a nice feature in most software unit testers: branch checking (in short: it's a hierarchical to-do list). I'll elaborate on what I mean. You need to check every path of execution of program branches (including nested ones). The program segments that contain paths that are yet unchecked are marked with a cross and are highlighted (usually with a color like red). After you are finished checking some paths of execution, those parts of the program source that are fully tested are given a tick and are highlighted (usually with different color). We would need a feature like this in our E-mail clients! It would sure help some of the people I exchange mails with. You see, there exist peers who are notorious of forgetting to reply to parts of (my) messages - often the most informative parts! I usually follow this up by kindly asking them to give an answer or give the answer of not telling. They often reply that they simply forgot to answer, or that they had an impression of ...