Word of mouth marketing -v- paid per post blogging

I'm hoping paid per post blogging was some niche fad that has just faded away. But I doubt it. People seem to like to think they can make a quick buck selling an opinion. I'm reading Guy Kawasaki's The inside word on word-of-mouth marketing.
Quote: Cash messes with our opinions!

Word of mouth marketing is tricky, great article though and it has a link to The Word of Mouth Manual, Volume II. Anyone know about volume I or am I being completely duh!?