HTML was designed as a flexible and generic markup language.
Unfortunately, it is a little too flexible and generic to be
really useful. The power of SGML comes from its ability to represent
the structure of a document faithfully, and HTML cannot do this in
most cases - it has a <title> element, and some structural
markup <Hn>, but apart from that, it's little better than
simple ASCII text. As well, it suffers from some of the same diseases
as LaTeX, as described above in Section 2.1, in that the
effective definition of a `good' HTML document is `viewable by
netscape', and that means that you're even less well-assured of the
content and structure of a document than you are if you use LaTeX
(if you are going to get involved in validating documents,
you might as well go the whole hog and do it properly).