cloudy and murkey "negative SEO"

there has been lots of talk about "Negative SEO".

however, there seems to be conflicting reports and it seems to be a murky area as to if it is technically possible. obviously Google are denying its possible but by the looks of things it is rife and "if you understand the rules of search...you can use them not just constructively, but also destructively."

...comforting thought for brand owners and agencies alike.