--- a/rdf-concepts/index.html	Fri May 18 12:27:15 2012 +0100
+++ b/rdf-concepts/index.html	Mon May 21 11:44:43 2012 +0100
@@ -904,9 +904,12 @@
     </dd>
     </dl>
 
-    <p class="note">Any language annotation desired in the HTML content
-    must be included explicitly in the HTML literal
-    (<code>@lang="…"</code>).</p>
+    <p class="note" id="note-html-context">Any language annotation
+    (<code>lang="…"</code>) or
+    XML namespaces (<code>xmlns</code>) desired in the HTML content
+    must be included explicitly in the HTML literal. Relative URLs
+    in attributes such as <code>href</code> do not have a well-defined
+    base URL and are best avoided.</p>
 
     <p class="note">RDF applications may use additional equivalence relations,
     such as that which relates an <code>xsd:string</code> with an
@@ -972,8 +975,9 @@
 
       </dl>
 
-      <p class="note">Any XML namespace declarations (<code>xmlns</code>)
-      and language annotation (<code>xml:lang</code>) desired in the
+      <p class="note">Any XML namespace declarations (<code>xmlns</code>),
+      language annotation (<code>xml:lang</code>) or base URI
+      declarations (<code>xml:base</code>) desired in the
       XML content must be included explicitly in the XML literal.
       Note that some concrete RDF syntaxes may define mechanisms
       for inheriting them from the context