To be more precise:
* Typewritten documents should have two spaces after sentence-ending periods.
* Word processed documents should use a single space.
* TeX and other typesetting programs often use a "long" space at the end of
sentences. It's more than a single space character, but much less than two.
Actually, I think most books don't do this any more. Newspapers certainly
don't. It's way too much trouble escaping out all the abbreviations. It
doesn't really add anything to readability.
I personally would prefer "one space fits all" as writers of HTML really
shouldn't need to know the fineries of typography (What's next? Range
kerning?), especially since it's not something 99.99% of people will notice
(i.e. it won't even look "wrong").
Then again, I didn't even notice until Terry mentioned so it's not a major
problem either way.
--ken chang
NCSA Publications