grokking char encodings

[rustom]

There is this page:
http://orgmode.org/worg/org-tutorials/org-custom-agenda-commands.php
which when I print under Firefox3 prints some spaces as unicode boxes:
in particular the ones in
<pre class="example">

Now this is not directly relevant to emacs except that when I open the
page under emacs (on a win XP box) the mode line shows
-1(Unix)....
but the file shows ^M at EOLs.
I am trying to understand what this means as a char encoding...
Can someone throw some light?
My own understanding is that both emacs and FF3 are being confused by
something... What?