The footer is an informal designation. In the head a viewer typically sees only a document title, usually in the top bar of the browser window. Other important information about the document can also be included but may not show within the browser window. The footer contains the fine print, and often additional navigation aids. Just remember that your page doesn't have to LOOK like it's divided into three parts.
Some effective pages treat the head and body as one design space.
Things you can't do without. Viewers may arrive at your page from anywhere on the Web. You can't assume they have any context for your document, so it must be able to stand alone, online or when printed out. E-mail address or other contact information Pages carrying official Penn information must also bear Penn's official Web Stamp, which is linked to a page that includes copyright notices and privacy information. If you include everything, make all the link anchors textual, and put it all in the footer, the bottom of your page will be very crowded.