HTML (hyper-text markup language) is uses tags imbedded in the text as suggestions for interpretion by the web browser software visitors use to view a site. These have meaning deeper than font sizes used in page layout or in print media. Consider the heading tags:
They not only change font size, but also classify the order of importance in a hierarchy. For example, suppose you want a heading to register as important
<h1>Important Heading</h1>
but it visually dominates the page more than you want.
There are a number of ways to handle this, but I prefer to control appearance with CSS (cascading style sheets). Both lines below are H1 level, but for the second one I have applied the class "soft" from my site style sheet making it less intrusive visually but preserving the interpretation I want.
In addition, should I later decide to use another color or a different typeface, I can do so for every place on my web site where I use the "soft" class simply by editing my style sheet.
Other common misuses of tags are:
<em></em>
emphasis
instead of
<i></i>
italics
for book titles, terms in a different language,
etc.
<blockquote></blockquote>
or
<dd></dd>
(definition list item) to produce indented text
If you are deciding whether to use a GUI program for constructing your web pages, in addition to appearance in your browser, check the page source for the above plus overuse of tables with cells containing
clearpixel.gif
images to control spacing. You can often improve performance and make maintenance easier by using HTML as it was intended to be used.