This idea isn't new. What is remarkable about this particular version of the concept is the ease, speed and relatively low cost with which the message can be spread using the Internet, especially e-mail. Recipients won't be able to restrain themselves from forwarding your message to their friends if it is incredibly cool, funny or visually stunning. Sometimes sheer entertainment value is enough. By providing recipients with something of real value, such as specialized information or an easier way to complete a repetitive or time-consuming task, you help them become more effective at home or at work.
Nothing is quite as enticing as money.
Discounts, product bundling offers, sweepstakes and free stuff are as effective as ever. Individual buyers are typically more attracted to incentives that benefit them personally, in contrast to, for example, savings that help their employers. Used unwisely, viral marketing can get you into trouble. Here are a few words of caution before you start. Don't breed spam .