Viral marketing describes any strategy that encourages individuals to pass on a marketing message to others, creating the potential for exponential growth in the message's exposure and influence.

Like viruses, such strategies take advantage of rapid multiplication to explode the message to thousands and then to millions.

Public health nurses offer sage advice at flu season: stay away from people who cough, wash your hands often, and don't touch your eyes, nose, or mouth.

Viruses only spread when they're easy to transmit.

Viral e-mail marketing works great on the Internet because instant communication has become so easy and inexpensive. Digital format make copying simple.

From a marketing standpoint, you must simplify your marketing message so it can be transmitted easily and without degradation. Short is better.

Remember the K.I.S.S. standard?.Keep it Simple Stupid. The shorter and easier to remember is always better than long and complicated.

Clever viral marketing plans take advantage of common human motivations.

The desire to be cool and greed drives people. So does the hunger to be popular, loved, and understood.

The resulting urge to communicate produces millions of websites and billions of e-mail messages.

Most people are social.

Nerdy, basement-dwelling computer science grad students are the exception.

Social scientists tell us that each person has a network of 8 to 12 people in their close network of friends, family, and associates.

People on the Internet develop networks of relationships, too. They collect e-mail addresses and favorite website URLs.

Affiliate programs exploit such networks, as do permission e-mail lists.

Learn to place your message into existing communications between people, and you rapidly multiply its dispersion.

If you can design a marketing strategy that builds on common motivations and behaviors for its transmission, you have a winner.