One thing that all decent web sites provide is a way for the visitors to the site to contact the site owner. There are a whole range of different ways to do this depending on the nature of the site. In some instances it is appropriate to provide your actual street address or post office box. Many business web sites also provide a phone number. Almost all provide some sort of contact form to allow visitors to send them an email.
XHTML provides a special tag that you can use to specifically identify this contact information inn your web page to make it much easier to identify.
Your contact address (regardless of whether you give the physical address, phone number, or link to a contact form) should be enclosed within <address> </address> tags so as to identify that the information is the contact details that you want people to use to be able to contact you.
This article written by Stephen Chapman, Felgall Pty Ltd.