Fourth, when I see a lot of advertisements on a site, my first inclination is to bolt; I try to dig a little deeper, but my antenna goes up when I see that I am going to have to wade through all those ads. I understand that letting other companies advertise on your site is a viable business model and, if it's done reasonably and the site is still providing me with real value, I'll tolerate it. But, sometimes the ads are so pervasive that you can't easily tell what the site can actually do for you, or what its purpose is; and the worst situation is not being able to clearly see the difference between an advertisement and content. Just remember - when you see a lot of ads on a site, the person paying for them is the real customer, not you!

Finally, not being able to clearly discern what the site's business model is and how it makes money makes me suspicious. I understand that most people are not going to have this one on their list; but, I believe there are only a three reasons to have a web site to begin with - to sell more, to enhance efficiency, and to provide better service - and if I can't figure out which one the site is trying to accomplish, it makes me a little uncomfortable.

At the risk of oversimplifying this credibility and trust issue, the real solution is to pay attention to it - to make it a point to probe how credible you actually are. As your site changes and evolves, keep testing it and find ways to get feedback from visitors about what they think. Give them a way to "look you in the eye" and you'll have a better chance of earning their trust.