I have hardly ever exercised a contributor's right to exclude certain comments from a thread I have opened, and almost always (perhaps always) it has been, not because of heresy or some other opinion with which I might happen to disagree, but because of vulgarity or some other offense against what I might call the intended tone of a thread. But this means that ones thread is at the mercy of anyone who might choose to comment and make it the occasion of expressing some pet concern, whether or not it has much to do with the subject of the thread, and thereby, especially if people take up the concern, to deflect attention away and even, in some cases, quite to defeat the purpose one had in mind in starting the thread. I can tell you I often find this quite disappointing and, sometimes, as most recently, even painful.Since the question of censorship has come up in connection with a few recent threads (one of them mine), I thought it might be useful to have a conversation about the matter which I would hope might involve both those who post at dotCommonwal and those who comment on posts. Should we include among our rules for participation that one's comments have something to do with the subject of the thread? Is "censorship" an appropriate category for this medium or conversation? Does one have a "right" to have anything one says included on any thread, no matter what its relevance to it?Etc., etc.