Why must there be a hard rule about top posting?
It is my belief that whether to 'top post' or 'bottom post' may largely depend on the characteristics of the medium. In USENET, bottom posting was preferred because messages often arrived out of order, and occasionally did not arrive at all, thus supplying the context of the reply before the reply itself would argueably increase the chance that a reply would be fully understood. Conversations might span days with only a very few contributions each day, and the context could be helpful. In modern Internet email, messages rarely are delayed very much, and rarely are lost in transit. In that environment, top posting allows someone who has been following the discussion closely may continue to follow it without the distraction of having to page past repeated text which he or she has already read and digested. But against simply omitting that context, at the bottom, it is there for those who would like to refresh their memory of previously-discussed points or for whom the mail did not arrive, or arrived late or out of order. Interleaved posting, such as might be used in a question-and-answer message, has a number of advantages over strict adherence to 'top' or 'bottom' exclusively. Conclusion: it pays to be versatile. - Brian