I met the developer who was responsible when I was employed by Amazon. He was trying to reply to an email, but I believe it was a "reply all" (if I recall the details of the story correctly) and the list was massive. Meanwhile, people on that same massive list were also doing a "reply all" to submit their feedback or reply that the email didn't apply to them. Massive email storm resulted. He didn't give all the details but he was ear-to-ear grinning as he told us the story.