How to Write like an Expert about Anything."
If you have a bunch of ideas, and present them in an unstructured way, you'll overload your readers. You have to make the data useful by structuring it, and organizing it into information.
If he were writing to software developers, he would be saying that when you present a message to a prospect, that software buyer needs to know the topic you'll be covering, as well as your "angle" or "hook" that you're using to describe your software. The reader needs to know how you've narrowed your focus, and how you've organized your thoughts into a useful theme.
If you're selling a Windows utility, and you're targeting three or four niche audiences, don't try to create a single sales message that will be understood by all of your prospects. Instead, create multiple sales paths on your website, and nudge each prospect into reading the web page that would best describe how your application can make their life better.
Structure your website for your target audience and you'll increase your software sales.