All this hyperbole over negative SEO seems based on rumors and speculations. Not much science going on here lately.
What is negative SEO? Is it anything within the realm of sabotaging your competitor’s website?, Well if so, that’s nothing new. Sabotage, has been practiced since the earliest days of the Web, and even before that on Bulletin Board services.
All these suggestions that the Penguin Update has suddenly made negative SEO possible via web spam seems patently false. Where is the evidence of this? Every test that I have heard of, that set out to confirm this theory, has failed to confirm it. Real science indicates it is an invalid theory, yet people go on, and on about it.
Admit it, you have been duped by this FUD, stop your spamming and start building something of real value.