"Reply All"

Someone explain what happened yesterday with the Department email thread?

Did the initial email have all the names in the "CC" section instead of making it a "BCC" letter so that "Reply All" wouldn't clog up everyone's boxes?

Something like that should have ground the Department Intranet to a slow crawl at the very least. 

And a hearty laugh to all who figured it out and hit "Reply All" anyway.