Index: xdocs/reference/repository-upload.xml
===================================================================
--- xdocs/reference/repository-upload.xml	(revision 124928)
+++ xdocs/reference/repository-upload.xml	(working copy)
@@ -71,6 +71,13 @@
           <li>currentVersion</li>
           <li>dependencies</li>
         </ul>
+        <p>
+          Some considerations about the <b>groupId</b>: it will identify your project uniquely across all
+          projects, so we need to enforce a naming schema. It should be equal to the domain name of
+          the site where it's hosted (e.g. www.springframework.org should be groupId=springframework).
+          If the project is hosted at a project hosting site (e.g. sourceforge) it should be equal
+          to the project id (e.g. oness.sourceforge.net should be groupId=oness).
+        </p>
       </subsection>
   
       <subsection name="Step 2. Posting the request">