The posts on this reminded me of something that happened a couple years ago, and how out of hand something as apparently innocuous as "reply to all" can be. I had ordered a computer from Dell, which was supposed to come preloaded with Windows 2000 and include an upgrade coupon for Windows XP. I already had Windows 2000 Professional and had no desire to put XP on it, so it wasn't a big deal to me.
Shortly after that, I got an email from Dell saying that the upgrade wouldn't be available for a couple months yet -- this was in September, the upgrade was offered to the public in October, and according to the email from Dell, the upgrade would not be available to their customers until November, and could be as late as March. Which, needless to say, upset a lot of the customers who bought the system they did or when they did because of the fact that they were to get the free upgrade.
But the worst part of all of this -- Dell hired a contractor to send out this email to all of the customers -- and this contractor addressed the email to all 129 of the people waiting for the upgrade -- and included all of the email addresses in the TO field, exposing everyone's email address to everyone else. With people being so upset about not getting the upgrade, there were a lot of nasty emails going back to Dell (with a reply to all); and then a number of people getting upset and either nicely or extremely not so nicely saying stop sending me copies of these (with a reply to all); and then other people coming back with "get a *$@: life and find your delete key" (with a reply to all); and so on and so forth; and one guy actually had the nerve to ATTACH HIS RESUME, in the hopes that someone on this list would be hiring. And naturally there are people that include sig lines to all their emails; or little pictures; or whatever.
This went on for MONTHS. I'd come home, and find hundreds of emails related to this, getting nastier as time went on, because everyone kept replying to all. There wasn't a good way of filtering them out and still get the necessary communications I expected from Dell. So it was a few months of email hell. At least I was using a home email address, I felt sorry for those people that were using business addresses. Dell apparently took a lot of heat over this faux pas (from me too!), because to make up for it, they sent us $100 on-line gift certificates.