This is an interesting book that is worth reviewing from a historical context given that it was written more than a decade ago in 2002. The technology may have changed but the fundamentals remain the same: brands that create good content can motivate networks to share marketing messages.
I'm not sure why earlier reviewers have been so harsh. Viral Marketing was of the original texts on internet driven word of mouth marketing and as such deserves recognition.
Steve Earl and I spoke to the author Russell Goldsmith and his colleagues when we were writing Brand Anarchy, and we collaborated on Share This, the crowdsourced social media handbook.