Work Email Etiquette

I find myself noticing articles answering the question what exactly one
may or may not write on work emails. Godforbid companies actually write
guidelines in the employee hand books.

Well, presuming companies are trying to save on cheap paper so coworkers
don't know how to write proper notes to each other anymore believing
emails are secret messages. I have been in trouble for inappropriate
notes I've written, but when one has no rules on what is considered
appropriate that is easy to do.

So what is allowed to be written on work emails from the company's
perspective without crystal clear rules being established. I'm guessing
from experience how to write proper work emails.
1. No editorials. Stick to facts of events at work. Nobody wishes to
hear about your personal problems or how bad your day is simply because
we have have our own issues too. Some will put it as "office use only".
2. Your company owns the work email addresses of its employees and can
read them. Many employ another business to read employee emails to scan
for unprofessional behavior. It is very stupid to complain about your
boss on work email for this reason. Nobody appreciates being talked
about behind their back. If you must whine about your boss, do it on
your home computer where your boss has no access.
3. If complaining about a coworker, stick to the facts what they did or
said to upset you. You can't read their mind anymore than they can read
yours. And don't take things personally, business decisons are based
upon money, not emotion. If you do not have the courage to complain to
their face, you should not email others about them. In other words, no
gossip (yes I am guilty of gossiping too and don't wish to hurt others'
feelings causing friction on the job).
4. Do not expect an immediate response. Many people don't access their
email all day, every day. If it is important, pick up the phone and call
them.
5. Keep your personal life at home and your office life at work. When
your personal life effects your job performance, like having surgery or
death in the family, then you can share at work. I know many bosses
compare their companies to a family and expect loyalty from employees,
but really who are they kidding? Family doesn't fire half their
workforce and transplant their lost jobs overseas where it is legal to
exploit employees, employers do.
6. Don't use caps unless stressing a point, all caps appear as shouting.
And get to a point in the first 2 sentences of why you are sending an
email. The shorter the email the better.
7. No dirty jokes, they can be misinterpreted by someone you do not know
well. And certainly no dowloading pornography on your work computer. I
have heard on TV of people getting fired for both of these actions.

If anyone reading this thinks up more etiquette, please share in my
comments section. Post later. Bye!