diff --git a/index.html b/index.html
index 2c2db95..2ecd771 100644
--- a/index.html
+++ b/index.html
@@ -1107,7 +1107,7 @@ <h3 content="Solid WebID Profile Data Model" property="schema:name">Solid WebID
                     <li>One <code>rdf:type</code> property whose object is <code>foaf:Agent</code>.</li>
                     <li>One <code>pim:preferencesFile</code>.</li>
                     <li>Zero or one <code>ldp:inbox</code>.</li>
-                    <li>Zero or more <code>pim:storage</code> properties to indicate agent's storages.</li>
+                    <li>Zero or more <code>pim:storage</code> properties to indicate agent's storages. If the WebID in an agent's storage, that storage MUST be advertised.</li>
                     <li>Zero or more <code>rdfs:seeAlso</code> to refer to related <a href="#extended-profile-documents">documents
                         extending the profile.</a></li>
                   </ul>