HTML 3.2 Mode is a major mode for Emacs (developed under GNU Emacs), which fastens up HTML writing by short-cuts for tags, entities and some useful functions like parameter quotifying, adding doctype string, etc. It is designed as replacement for the HTML (1.0) Mode (htmlmode.el) by Marc Andreessen email@example.com from the NCSA, but both can be used together on one system / Emacs, too.
It's no more up-to-date for over a decade now. It was written back in the 90s for GNU Emacs 18 and 19. It no more works since the syntax highlighting API has been redesigned (with GNU Emacs 20 or 21 if I remember correctly). The last time the code has been touched was back in 1999. It neither knows about HTML4, XHTML, HTML5 nor CSS. It's just still here for historical purposes. Don't use it, try html-helper-mode instead.
HTML 3.2 Mode is not a mode for browsing HTML documents. In particular, HTML 3.2 Mode provides no hypertext or World Wide Web capabilities. It is not a syntax checking mode, either (Although it provides some error correcting routines...). It´s also no WYSIWYG mode. (How could it be? It´s an Emacs mode. Hmpf!)
See ftp://ftp.cs.indiana.edu/pub/elisp/w3/ for w3.el, which is an Elisp World Wide Web browser written by William Perry.
Looking for compact HTML Reference? Have a look at The HTML 3.2 Short Reference.
The official HTML 3.2 recommendation and the SGML definition of HTML 3.2 can be found at the W3 Consortium.
Thanks to Eva ´Ms. Emacs´ Stopp for beta-testing the HTML 3.2 Mode, for implementing the help on the special characters and for providing HTML 3.2 Mode on all Emacs installations, she administrates.