RE: Navigation Tag

In addition to the LINK element, regular A elements support both rel/rev 
attributes, to state the relation of the href document to/from the current 
document, and the accesskey attribute.  These relations 
(http://www.w3.org/TR/REC-html40/types.html#type-links) include start, 
next, previous, contents, glossary, and other useful relations.  The 
specification even states, "User agents, search engines, etc. may interpret 
these link types in a variety of ways. For example, user agents may provide 
access to linked documents through a navigation bar."

At least the accesskey attribute is (a bit clumsily) supported by IE5; when 
specified on an A element, use Alt-{accesskey} to select the anchor, and 
Enter to follow the link.  (I haven't checked 4 for this.)