E-mail etiquette

I just happened to read an article in Real Simple about e-mail etiquette. Thankfully, I've discovered that I'm current with what is/ isn't polite, but apparently some of the parents I correspond with are not.

According to the article, you should include a salutation and closing when sending an email. The only exception is if you are sending one to a friend whom you correspond with regularly. Otherwise, include both. Well, the weekly progress reports that I email home to parents usually generate a response. While some parents include the required (and proper) salutation and closing, others neglect both. Thus, I have to figure out who is addressing me and how I should address him (or her). I find it frustrating that in an age of communication there are plenty of adults who do not know how to correspond with professionals properly. Whenever I email parents, I be sure to address them by their last name, and end the email with my signature/ name. When they don't extend the same courtesy to me, it's almost as if they are addressing me as a peer, or worse, as an inferior.

So please. Be sure you follow email etiquette. And feel free to call me on those times when I fail to do so.