I have seen it happen before, with no warning. Usually it happens only after the individual has embarrassed themselves, and it seems to be a face-saving measure, but other times, they just get frustrated, thinking they won't change anybody's mind anyhow. I think it is when they realize that their inability to argue, makes the other side look so good, they would rather pretend that the debate didn't happen.But to delete everything? I wasn't a part of the conversation and haven't read every reply. Did she begin to turn around in any of her comments, or just go awol all of a sudden?