Don't use tabs

[SVN r30602]

more/discussion_policy.htm

@@ -89,6 +89,14 @@ The Boost developers' list is a high-volume mailing list, and most
 maintainers don't have time to read every message.  A tag on the
 subject line will help ensure the right people see your post.
 
+<p><a name="tabs"></a>
+
+<h3>Don't Use Tabs</h3>
+
+If you use tabs to indent your source code, convert them to spaces
+before inserting the code in a posting.  Something in the processing
+chain usually strips all the indentation and leaves a mess behind.
+
 <p><a name="quoting"></a>
 
 <h3>Don't Overquote</h3>