Feedback can help you provide customers with the right information.
Customer feedback is one of the things you just don't get with other forms of advertising. There's a lot of feedback you can get with a website without doing too much at all.
Something simple like a counter lets you know how many people are looking at your site. You can immediately see what promotions work and what doesn't work by the frequency of visitors. If you place an advert in vogue and your visitors suddenly skyrocket, you'll know that you spent your advertising dollars well. If there's no extra visitors then you'll know the opposite is true.
Customer surveys is another great way to find out the type of people visiting your site. Find out why they visited and what would make them come back simply by asking.
Have you provided enough information to the reader? Find out by asking them. Include a form to make it easy for them to ask you more questions. You can add the extra information required into your site so all of your future visitors will have the right answer first time.