I've been reading a lot of Seth Godin's blog these days. For all of the talk about new trends in marketing, especially Internet marketing, Seth's messages provide a consistent foundation that is becoming more and more helpful to me... which is why what I'm going to say next may sound odd. I think Seth missed a key point in today's blog posting titled "Is viral marketing the same as word of mouth?" While I'm hardly qualified to disagree with Seth, I think he omitted why word of mouth and viral marketing are different. Seth says:

Word of mouth is a decaying function. A marketer does something and a consumer tells five or ten friends. And that's it. It amplifies the marketing action and then fades, usually quickly. ... Viral marketing is a compounding function. A marketer does something and then a consumer tells five or ten people. Then then they tell five or ten people. And it repeats. And grows and grows. Like a virus spreading through a population. The marketer doesn't have to actually do anything else. (They can help by making it easier for the word to spread, but in the classic examples, the marketer is out of the loop.) Read more >