You can make a list of them and offer it. Make sure, though, that you have a great list. An extensive list of free advertising tools such as ad submitters, FFA sites and classified ad sites might do the trick. Remember that anything you offer for free must be useful to your potential customers. It must serve a purpose for them and that they can get something out of your free product.
People tell other people what they like.
If they like your free viral marketing tool and they tell other people about it, they also tell them about you and your e-business. Another way you can use viral marketing to your advantage is by offering a special free bonus on purchase of your product. This is a technique used mostly by affiliates of other people's programs. You offer more than what the company you are promoting offers, making more people buy from you. If you're reselling a program where people are requiered to place ads, offer them a free training report on how to place ads effectively and a list of advertising sites.