Viral marketing describes any strategy that encourages people to pass on a marketing message to others, demonstrating an important potential for exponential growth in the message's exposure and influence. Viral marketing has become one of the most effective and cost-efficient ways to create a "buzz" about firms' products and servi­ces. Like viruses, viral marketing strategies take advantage of rapid multiplication to exp­lode the message from thousands, to millions. On the Internet, it is any marketing techni­que that induces web sites or users to pass on a marketing message to other sites or users. Word-of-mouth techniques are vital to marketing on the Internet. Consumers tend to the primary source of credibility. On the Web, viral marketing has been called also "word-of-mouse" or "word-of-modem". Viral marketing on the Internet is the simple technological extension of word-of-mouth marketing. On the Internet, an effective viral marketing stra­tegy includes six elements: gives away products or services, provides for effortless trans­fer to others, scales easily from small to very large, exploits common motivations and be­haviors, utilizes existing communication networks and takes advantage of others' resour­ces. Successful viral marketing campaigns are comprised of engaging message that invol­ves imagination, fun, easy use and visibility, credibility, encouragement and customizati­on.