<A target="_blank" href="http://online.wsj.com/article/SB10001424052748703386704576186520353326558.html">We've been using e-mail for years now. And, the dread "Reply All" button</A> has been there for most of that time. Which has lead to any number of snafus that could probably have been prevented. This article includes a chart showing how an e-mail storm escalates.