In the morning, while brewing my coffee, I use my phone to look at the emails that have arrived in my work account overnight. Generally there are about a dozen, most of them from automated jobs. In most cases, I can judge from the subject line whether I can delete the email or must read it and follow up.
Friday morning, there were about 370 emails. After I read a few, I understood what had happened. Somebody at NetApp, which makes the storage units we use, had sent out a bulletin using the CC field rather than the BCC field. A few techies sent out a reply to all, and then more sent replies to ask what was going on, or to ask others to quit replying. One ordinarily imagines techies as understanding the pitfalls of using Reply All; and perhaps we are less apt to do so, but for a sufficiently large mailing list it doesn't take a large percentage to create this sort of storm.
The incident did show the ubiquity of NetApp gear. I saw replies in French, Italian, Russian, German, and perhaps would have found more languages still if I hadn't been in a hurry to get rid of them. A young and mobile systems administrator could have built up a list of organizations to apply to, and perhaps of responsible parties within them.