Increase visitors...

If the site looks different every time somebody visits, they'll be more inclined to come back again. If the content is customized to them individually, then you can 'target market' your information, and improve your odds of succesfully reaching that person.

You might want to think about doing a complete site redesign every few months, as it not only keeps it fresh, but it also gives you the opportunity to take advantage of newer technology as it comes out. This also helps to improve your site as time goes on, as you'll invariably learn better techniques through each iteration.

Web Design