Advertising is also about appealing to senses and emotions rather than intellect. The 'Net is based on substance, content and context. Take a look at Volvo's homepage for a good example of the problem. Your ability to interact with Volvo is limited. If I can't find a car that meets my needs, I am not given a link to another carmaker's homepage.
People get on the 'Net, and the Web, in search of information.
Even while surfing, 'Netters follow a threat that has some common denominator that leads them from one to another. If there is no substance in the information obtained in that search, the message will be annoying and intrusive rather than inviting and useful. I am involved in the development of a Website for my professional association, the International Association of Business Communicators. We intend to clearly state what IABC is, what we do, what the advantages are of joining. We also intend to provide links to resources of value to communicators, whether they're members or not.