Because I am on the road a lot, I read a lot of email on my phone. In fact, I will often scan an email on my watch before deciding whether it's even worth getting the phone out to read it.
Too often, people treat email like it is the electronic equivalent of a letter. They will put flowery language up front, ask about the kids, etc. I'm not saying that there is no place for that in email, but LifeHacker is absolutely right. If you want to ensure your email gets read, make your point or ensure the you grab the reader's attention in the first line.
Pay attention the next time you get email on your phone. Notice how little of the message you actually see. If you don't have some of the important stuff up front, it might not ever be opened by those of us who rely on our phones for email.
What about the subject line, you ask? I find subject lines to be helpful, but lengthy subject lines can get cut off sometimes. Focus on that opening line. Ask about the kids later.