The term viral marketing was allegedly coined by Steven Jurvetson, one of the original investors in Hotmail. He used the term to describe how fast the Hotmail service grew with minimal input.

And now viral marketing is one of the most exciting yet misunderstood areas of e-mail marketing. It's not just a matter of sending a humorous animation or video and hoping it gets passed along. There is a lot planning to do regarding list and distribution management as well as design, to get it right the first time.

To succeed, you must ensure your e-mail is distributed to the right influencers first if you want it to get distributed at an exponentially growing rate. Do you know who the best influencers are for your message?

After all, what use is an e-mail that gets passed along, if you don't encourage some kind of response or involvement from the recipients? Just hoping you create "awareness' of your e-mail is no guarantee of any success.

The idea within the e-mail is the key to creating a viral effect. If your message is too difficult to understand, or e-mail is too hard to open then it will die a quick death.

And don't forget, bad news travels as fast as good, so you want to be sure you and sending messages that will be supported positively, not negatively, by recipients.

One of the other reasons viral marketing works so well, is the fact it has worked extremely well off-line for decades, through member-get-member programmes. Like most of the on-line successes, the best are those that use existing ideas and just apply new technology to improve them.