When you see a mail lying in your inbox having multiple people in the CC and in the To, the first urge is to hit the Reply-All button. Make your presence felt in the email conversation. The urge increases exponentially with power distance (also see Geert Hofstede) in that organization. The minions have to prove to their bosses that they exist, and they can contribute for the bosses benefit.
You will see this become excruciatingly apparent on public holidays, company-wide announcements, successful projects, etc. The reason I am posting this today is because I know that my inbox is going to get inundated with Happy Independence Days tomorrow. Despite repeated requests, this does not change, so I say, let the spam spew forth.