I am on several lists; Recently one of them had a discussion about deleting previous messages before replying to them so as to aid digest subscribers. It turned out that only a few people subscribed to digest versions and the discussion revealed that the original reasons for having digests were really not that beneficial anymore with advances in the technology. Of course those used to digests did not always see it that way. On the other hand non digest users often found that posts that were replys to messages often made no sense unless the original message was attached. On that list it was decided to keep the original message in the reply althought that does not mean one needs to continue a whole stream of messages. It appears that what is curtesy to one group is an afront to another. I don't think there is any answer to this.