The biggest tip I got out of it was a reminder not to be Bullhorn Guy. Online relationships are not as different from real ones as we think. If I don't know you, if I don't trust you, I don't really care what you have to say. You must not presume a position of authority.
So, stop selling, stop asking for favors, and start trying to help others. Become a helpful knowledge resource in whatever industry you're in. And once I see that everything you say is not completely directed toward selfish purposes, I'm going to start listening.
In fact, I really think the parables in this book are as equally relevant to modern-day Christians as they are to online marketers.