In Ray Bradbury's short story "A Sound of Thunder", a group of people travel millions of years into the past to hunt dinosaurs. One of them accidentally steps on and kills a butterfly, which dramatically alters the future.

This idea was also taken up in a movie called "The Butterfly Effect", starring Aston Kutcher, about a young man who managed to travel to his past and, by altering earlier events, changed outcomes in his future, including some that were unforeseen.

The butterfly effect has its roots in chaos theory, where a small event can have a ripple effect and bring about possible dramatic changes - the fluttering of a butterfly's wings possibly forestalling a monsoon that would have devestated an island.

Successful internet marketing is the result of many such "trivial" events at work.

But which ones will prove to be significant and how do we sustain, and even build, the momentum which is generated?

One proven technique is known a viral marketing, which adopts a strategy that encourages many people to pass on a marketing message to others. It makes use of multiplication to "explode" the distribution of the message by willing participants.

Hotmail used this method to get established. When the two founders set up their free email system, all the messages that were sent by subscribers had a text message at the bottom which identified Hotmail as the origin. People would send emails to their friends, who would be tempted to set up hotmail accounts and send emails to their friends...

Within 24 months, Hotmail had 22 million subscribers, eventually selling out to Microsoft for about $400 million.

The viral marketing method is:

a. Cheap. Most approaches take just a little time to set up and then others promote your business for you.

b. It has the potential to reach a large audience by geometrical progression, limited only by the enthusiasm of the participants.

c. It can be effectively combined with other forms of promotion.

d. It's also possible to sell other products than the one you originally targeted. For instance, if you are selling garden products, those interested in flowers could also be interested in a catalogue that contains material on lawns, trees, landscaping, garden tools, etc.

e. A viral product is fairly easy to create. It includes ebooks, articles, branded software, audio and videos, free reports, or even the first three chapters of your ebook.

f. A quality product that users are willing to pass on to others is accompanied by an implied recommendation. They are effectively building your reputation.

Special Considerations:

1. Whatever the product is that you use, it should be of significant value and free - or of very low cost in relation to its perceived value. But usually it is free and easy to pass on.

2. Make it easy for people to pass on by using buttons, active links, tell-a-friend windows, etc. Many products also combine very well with an affiliate program when the affiliate receives some extra benefit from promoting the viral message. For instance, by being able to brand an ebook the affiliate gains credit when a reader buys through a branded link.

3. Buttons and links are not interchangeable. Many email facilities do not handle HTML well, especially those that are web-based. Codes can be easily corrupted. Use active links in emails and save buttons for web pages.

4. Be sure your message includes a clear call to action. There should be no doubt about what you intend recipients to do.

5. The INCENTIVE should be clear to those you want to act.

6. Offer clear instructions so that recipients know HOW to act.

7. The action you require should be simple and obvious. Don't complicate it or confuse the reader, such as by adding numerous links.

Viral Marketing is but one of many techniques that together have a cumulative effect in attracting customers and subscribers to your business - in attracting targeted visitors to your website. Momentum is gained by aiming every element of the overall strategy at developing the relationship with your visitors. The momentum builds as it succeeds in identifying YOU as one of the white hats - someone who can be trusted to provide value and a solution.

Design your strategy in such a way that there is a positive flow-on effect into the future rather than one which diminishes after the initial zeal and enthusiasm which launched your product.

Focus on delivering benefits to your visitors and making it easy for them to collect. And don't step on the butterflies.