Think of them as the Yahoo's for the affiliate world. There is a science and art of traffic analysis. This article covers both. Indeed, competition is thick. It's been etched in our collective psyche as online merchants that some consumers have a tendency to distrust Internet businesses.
Many people are wary of buying goods or services online.
You can spend every waking moment promoting your site, but if it's not a well designed site to begin with, you're fighting a losing battle. Good sites help to promote themselves. You should always submit your site to the major search engines and do what you can within reason to try to ensure a good listing. But there are other ways to promote your site and these other methods might just work as well as, or in some cases better than, search engines and directories to refer people to your site. As with anything in life, there's a right way and a wrong way to use the Internet for marketing.