There are many ways that you can use Skype's free services to market your website and offline products too. First of all there is the possibility of being present online 24/7 for your customers. And since you will have someone or the other manning the computer with Skype running in the back ground you can have them dedicate some of their time browsing the categories of Skype's chatting services and singling out contacts of people who might be interested in your services or web site products.