Viral marketing is a very powerful and well established marketing technique. As well as being extremely cost effective, viral marketing extends over the long term and if done well can gain an almost unstoppable momentum.
So what is viral marketing exactly? Quite simply it is any sort of marketing materials that encourage the message to be passed on from person to person – hence the name.

A classic example in internet marketing terms is a viral eBook or report. You create an eBook on something that people in your niche will be interested in, and then inside the report you place links back to your websites. If the report contains something of value it’ll be passed on because people will want to share it with others. Your links or advertising contained inside the report will be seen for years and years after you originally created it.
What about other sorts of viral marketing?

A popular thing at the moment is viral videos. You only have to look at the popularity of sites such as YouTube to see the massive power of video as a way of marketing your business. The same principles apply to viral videos as viral reports – it needs to be something interest that people will want to share with others. Videos which are amusing, funny, or thought provoking in some way tend to do well. You need to get creative and produce something people will want to actually spend a few minutes watching.
Another form of viral marketing is email and email signatures. The launch of the email service Hotmail used viral marketing to great effect - at the bottom of every email sent through the service was a link back to where users could sign up themselves. This became very successful as more and more people used the service to send emails.

In order for viral marketing to be as effective as possible it is important to actively encourage people to pass on your materials. Make it easy for them to do so. If you’re creating a viral report, for example, a good strategy is to include a sales page with the report. Other internet marketers can then plug it in and distribute it to their customers without having to do much work.