In the spirit of several wise opinions I cut the prerequisit to a minimum (=0)
I participate(d) on many lists in several (intellectual?) topics. Almost all of them had periods when dogooders or aggressors wanted to moderate the list into oblivion. Then the lists survived the troublemakers and lived on. Somebody remarked already that it may be hard to find an off-topic topic in "everything". Unless: a new title like "everything "I" find topically interesting" but that would be a different list. IMO it is not offending if somebody writes some 'intelligen' idea which others may deem revolting, because it is not physics. Everybody has a 'delete' button on the computer. It would be a loss to exclude thoughts. On several lists the participants kept the unruly at bay without calling in Draco. John Mikes

