Isn't that strange? I'm a business user (have my own company for about 15 years now), I have been using Mail for at least 23 years, longer than most oft PHBs have heard of the concept. Nevertheless, I have no use for all the concepts the article thinks are so incredibly important. Flags? Why not just answer emails and archive/delete them? Junk Filter? Doesn't your server do most of the work? Rules? To automatically archive messages you'll never read? Why not just unsubscribe from all those mailing lists?
Some people forget that new tools often mean that old process are no longer meaningful, and that the tools needed to support those old processes are obsolete. So the troll who posted the article should try to get in sync with the present in order not to become obsolete himself.