I have been working online for a few years, and do scrape a moderate living. However, I would not mind investing in information that would help me improve. Tips that would increase my sales by 5 or 10 percent would make information valuable to me.
However, I just invested in another e-book that came recommended by people I respect, and durn it all - it was 90% rehashing of stuff I read for free on somebody's blog (or here) before.
I think it would be great for a newbie, and it would have saved hours of reading blogs, and no - I don't think we should have to just give everything away! I wish I could find material that really was geared towards taking an o.k. affiliate to the next level.
Though actually, the value of the book really might have been looking at the author's websites and reading 'between' the lines to things he never mentioned in the book.