The following was written by a friend at a forum I frequent. I think that it bears repeating here.

"While many people have a dry wit and sarcastic sense of humor, this kind of humor isn't welcome in the midst of serious and heated conversations. Be aware that English isn't the first language for our international members. Other members are deaf and use ASL. Still others have learning disabilities and are greatly challenged in written communication. Sarcasm doesn't translate well for many of these people and for many others, particularly those who have been the brunt of sarcastic jokes in their lives. In the sharing of passionately and deeply-held beliefs, sarcastic humor, no matter how well intended, can come across poorly to the one hearing it and for the one using it, it can be a way to hide real feelings behind a smilie face and a "I'm just kidding" comment. Sarcasm can be a rather passive-aggressive way to say what we're really feeling and in a grace community better that we find ways to communicate authentically and respectfully."