Index: en/book/ch03-advanced-topics.xml
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--- en/book/ch03-advanced-topics.xml	(revision 4295)
+++ en/book/ch03-advanced-topics.xml	(working copy)
@@ -2417,6 +2417,31 @@
         expansion.</para> 
     </warning>
 
+   <warning>
+     <para>A note to MS Office users:</para>
+
+     <para>Subversion can be used as a simple document management 
+      system for Office files. It is possible to apply the svn keyword 
+      substition on a doc file; however it is not recommended.</para>
+
+     <para>The reason: A doc file is not (or only partial) human 
+      readable. It contains both textual and formatting 
+      information. The text can be read using a simple editor like 
+      notepad, but the formatting info is in a binary format. The keyword 
+      substitution is not able to distinguish these different information 
+      entities. If applied on the document it can successfully substitute 
+      on the textual part. But it will also try to execute the replacement 
+      on the binary part and will replace a binary block if it matches a 
+      keyword. Which results in a corrupted doc file.</para>
+
+     <para>The keyword substitution is able to operate on the textual 
+      information of a doc file. It is however not able to operate on a 
+      docx file. Reason: A docx file is technically a compressed 
+      archive; the textual information can be found in an XML file within 
+      this archive. Subversion has no knowledge of this format; it is 
+      not designed to handle these kind of files.</para>
+   </warning>
+
   </sect1>
 
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