How does buzz marketing differ from ordinary word-of-mouth marketing?

"Much of sales promotion and publicity is about creating buzz. Buzz marketing (or viral marketing) is intense word-of-mouth marketing. Word-of-mouth is essentially a linear process with information passing from one individual to another, then to another. A marketer has successfully created a buzz when the interactions are so intense that the information moves in a matrix pattern rather than a linear one and everyone is talking about the topic. Leading-edge firms now feel that they get more bang for their buck using buzz marketing than other forms of promotion."