How to put comments into an HTML file

The correct way to put comments into an HTML file is by enclosing them
between "<!--" and "-->" markers, <!-- like this example --> shows
you.  If you forget the exclamation point, then you're not really
creating a comment: some browsers might ignore the text you've put
into this "new tag" that it doesn't know about, but other browsers
might decide to display your text, or even do other strange things
because of it.