LaTeX provides the facility to automatically cross-reference various sections, tables, figures, pages etc whereby the author does not have to keep track of the actual section, table, figure, page numbers - LaTeX will insert the relevant values when it is run.
This is useful since it allows the author to change the order of
such sections, figures, tables etc without having to go back through
the text changing references to them. Furthermore
this facility is particularly useful with documents to be
processed using latex2html, since latex2html
create hyperlinks to the relevant html page, figure, table etc
allowing readers
to easily find and view the referenced item
(if desired).
Details on what items can be internally cross-referenced with LaTeX are listed in Section 7.1.1 along with examples.