That's basically using an audience of 1. Starting with yourself and checking if it sounds right. After that, you'd probably bounce it to a few people in the o

That's basically using an audience of 1. Starting with yourself and checking if it sounds right. After that, you'd probably bounce it to a few people in the office, see what they think. They might pick up on something that sounds clear to you, but doesn't make sense to other people. Finally, you would want to bounce it to a few customers. Everyone inside the company is going to have a similar set of knowledge and assumptions when they look at the email, the only way to really be sure is to send it out. I don't think he's saying you should write down some random thoughts and test them, but rather as a final proof-reading step before sending it out to everyone.