The Customer Experience completely determines the success of web site and underlying business. However, the Customer Experience is rarely well understood by decision-makers of the site design, and rarely impacts the initial launch. What you don't know is hurting you. Most decision-makers of web sites don't really know how the site is doing. Or, in some cases, they don't understand why it is not doing very well.
Many site managers lack meaningful customer feedback.
Without using methods that realistically allow for them to observe what happens with customers using their web sites, they will continue to operate in the dark. They are effectively operating a business blindly. The whole web site and e-business phenomena is still very new. In the end, the best businesses depending on user-centered methods for web design will thrive. Those that do not know what is going on with their customers will simply not be around in the long run.