I’ve long thought that email clients are due for an overhaul. I enjoyed this paper from the SIGCHI 2005 conference. It’s as enjoyable for their work done as it is for the overview of prior art, which includes this Life Hacks-ish note:
Whittaker and Sidner [27] also examined how people responded to the abundance of electronic mail they received. According to them, people fell into one of three categories, depending upon the strategy they used for handling email: frequent filers constantly cleaned their inbox, spring cleaners cleaned their inbox once every few months, or no filers did not clean up their inbox and used search tools to manage it. Research to identify and compare different strategies for email management has continued.
The paper they cite, Whittaker and Sidner is excellent. Now to tie down the authors of Outlook and Mail.app, tape open their eyelids, and force them to read it …