I have (jokingly!) advised of my self-created 'So ...' rule - it applies when people preface their post with 'So ...' which guarantees that the remainder of the post will either have completely missed the point being made in the post to which the response is addressed, or, equally common, the response will say that it is answering a post, and then make a completely different point, underlining that the writer has failed to grasp the point being made.
This has not gone down well with some of the more curmudgeonly members of the AB - but that does nothing to dent its validity!