Godin sold his startup to Yahoo. He is now 'acting on it with his bootstrapped 'user generated content'-startup Squidoo. I doubt as a millionaire he needs the revenue from his books and speaking gigs to make a living.
That's kind of the point. If you want to know what it takes to eke out a living from your web project, it's good to ask other people eking out a living from their web projects, rather than a very talented marketing guru who is a couple of decades removed from having to worry about that class of problem.