Several Excellent Points - Unfortunately
In an age when email has moved from being a sort of quick note to being a replacement for regular business communications, several of the most accurate points made in this article simply highlight the catastrophic failure of the US educational system and the resulting abysmal lack of standards among too many "educated" "professionals."
We have to keep email short because people are too lazy to read more than two or three paragraphs (actually, many executives are incapable of paying attention to more than two or three sentences).
People need to be reminded to check spelling and grammar using the tools in their software because so many people have turned off those tools because they find all the corrections annoying. We have an education system that teaches students that spelling and grammar are obsolete concepts that no longer matter. In the business world, spelling and grammar often do matter, but the "spell check" built in to most software if woefully inadequate for the task today. How many emails and letters do each of us read every day that contain words which are spelled correctly - except that it is completely the wrong word. Most grammar checkers are incapable of handling anything much more complex than See Spot Run. Which may not be a bad idea considering how few people can write - or read - anything above that level.
And one point that Ms. Harkins omitted, pay attention to the difference between TO and CC addressees.