The workplace inbox is populated by a consistent cast of email types. They appear in every organization, in every industry, at every level. Here is the complete taxonomy.
The Drive-By
A brief email that drops a task, question, or problem into your inbox and disappears. No context. No deadline. No indication of priority. "Can you look into this?" The "this" is a link to a document you have never seen. The sender is already in their next meeting.
The Novel
Eight paragraphs. Three attachments. A request buried in paragraph six. The sender has been thorough. The recipient has read the first paragraph and the subject line. The request in paragraph six will not be addressed until someone follows up.
The Passive-Aggressive Reminder
"Just circling back on this." "Wanted to make sure this didn't get lost." "Following up again." Each one is technically polite. Each one communicates, with increasing clarity, that the sender is aware you have not responded and would like you to do so. See also: What "Per My Last Email" Actually Means.
The Witness Collection
An email that CC's three people who do not need to be CC'd. The CC's are not informational. They are witnesses. The sender is documenting that this communication occurred. The recipients understand this. Nobody acknowledges it.
The Announcement Disguised as a Question
"I was thinking we could move the deadline to Friday — does that work?" The decision has been made. The question is a courtesy. The correct response is "yes" or a very good reason why not.
The Thread That Should Have Been a Meeting
Fourteen replies. Six people. A decision that could have been made in five minutes of conversation. The thread is now three days old and the decision is still not made. Someone will eventually schedule a meeting to resolve it.
The FYI That Requires Action
Subject line: "FYI." Body: a situation that clearly requires a response. The sender has labelled it as informational to reduce the pressure on the recipient. The recipient is not sure if they need to do something. They defer. The sender follows up.
The observation: Most email problems are subject line problems. An email with a clear subject line that states what it is and what it requires is harder to mishandle than one that does not.