Clarify redirection, add rationale

[SVN r16623]

more/lib_guide.htm

@@ -270,8 +270,14 @@ library, but a reasonable effort to comply is expected.</p>
   </table>
 </blockquote>
 <h4><a name="Redirection">Redirection</a></h4>
-<p>If the documentation is in a doc sub-directory, the primary directory should 
-contain an index.html file which redirects to the doc subdirectory:</p>
+<p>The primary directory should always contain a file named index.html (or 
+index.htm). Authors have requested this so that they can publish URL's in the 
+form <i>http://www.boost.org/libs/lib-name</i> with the assurance a 
+documentation reorganization won't invalidate the URL. Boost's internal tools 
+are also simplified by knowing that a library's documentation is always 
+reachable via the simplified URL.</p>
+<p>If the documentation is in a doc sub-directory, the primary directory index.html file 
+should just do an automatic redirection to the doc subdirectory:</p>
 <blockquote>
   <pre>&lt;html&gt;
 &lt;head&gt;
@@ -435,7 +441,7 @@ suggestion.&nbsp; Major contributions are usually acknowledged in the
 documentation, while minor fixes are often mentioned in comments within the code
 itself.</p>
 <hr>
-<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->19 September, 2002<!--webbot bot="Timestamp" endspan i-checksum="39348" --></p>
+<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->16 December, 2002<!--webbot bot="Timestamp" endspan i-checksum="38515" --></p>
 
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