Congratulations if you've managed to put your site online, but your work isn't done yet. It's essential that you look continually for ways to improve the user experience. Numerous tools allow you to customize how your site looks for individual users and to increase levels of interactivity. Companies like BroadVision sell products that allow a webmaster to provide features such as product recommendations, targeted ads and automatic e-mail responses to questions.
Consider other ways to personalize the site for customers. Some news and shopping sites allow users to set preferences for content based on the region in which they live. A shopping or tech support Web site might provide a user with a series of questions that eventually leads to a few potential products (or solutions, in the case of, say, a tech support or medical site).
Think about other interactivity tools like discussion forums or a blog that allows readers to comment. Don't just throw up these features and hope they stick; integrate them into the life of the site, cross-link with other content on the site and keep them refreshed with new content. But don't forget that any feature that allows users to contribute may require some extra work on your part, as you'll have to keep an eye out for disruptive or inappropriate comments.
Although there are numerous possibilities for expanding a site's functionality, don't overload on features, flash, videos and other gizmos that may overshadow the purpose of the site or overwhelm the user with content. A video message from the CEO might seem cool, but it's probably not necessary for a site hawking band T-shirts.
Even so, keep the site fresh. That doesn't mean that you have to change the content just for the sake of doing so. But including updates on products, the company, the field in which the business operates -- all can help to keep users coming back and feeling as if the site has more to offer than its competitors.
Above all, make sure your site is straightforward and useable. If you can't afford some sort of focus-group testing, try it out with friends and clients. Solicit feedback. Make sure that there's a clearly marked portion of the site where users can contact you. You want to appear open to concerns and suggestions for improvement. Network with others in your field -- it can help you to learn what works and also to exchange useful information and contacts.