Whenever somebody sends out an openly addressed e-mail with 100+ recipients (or more!), I always say, “Oh boy! Here comes a party in my inbox.”
The “reply all” thing from the recipients springs into action, and your inbox is busy for days, maybe a week or more.
Then there is the bonus of extra spam from people’s compromised address books.
I feel like posting the attached image as a tutorial, but I don’t want to get into it right now.