I finished the book a little while ago. I found the advice it contains useful, even though my work as an editor has nothing to do with webcomics.
My favorite part, though, was your discussion of developing a fanbase, superfans in particular. Being a fan of both your and your wife's work, I'm concerned about crossing that line between fan and creepy guy. It's nice to hear that not only am I not the only hyper-enthusiastic fan out there, but that you try to develop fans like this (to a certain degree).