I'm sure company-internal vs. external email tends to be handled differently but here's one amusing bit of information my boss at Amazon once told me about Bezos.

He said if Jeff forwarded something to him (another email or even a news article) and didn't add anything else to the message then this meant "I expect you to know about this topic/issue, deal with it as needed, and be prepared to talk about it if I ever ask".

However, if he also included a single "?" at the top of the email, then the rules changed and it meant "I expect you to look into this and send me a reply/update as soon as possible".

I'm sure Jeff managed to triage huge chunks of correspondence using only the 'forward' button and the question-mark key.