The most basic type of viral marketing is first hand knowlege of a product or service.
Someone purchases a useful software and tells their freind about it.
This company also has the option for clients to subscribe to their newsletter from this page. This is also a great way to build a qualified database for a direct marketing campaign. They went bankrupt 3 months later. Someone purchases a useful software and tells their freind about it. This company also has the option for clients to subscribe to their newsletter from this page.