diff --git a/spec/index.html b/spec/index.html
index 7c24044..548eb18 100644
--- a/spec/index.html
+++ b/spec/index.html
@@ -503,6 +503,10 @@ <h3>RDF Documents and Syntaxes</h3>
 </section>
 
 <section id="conformance">
+  <p id="advisement-levels">The key words “strongly encouraged”, “strongly
+  discouraged”, “encouraged”, “discouraged”, “can”, “cannot”, “could”, “could
+  not”, “might”, and “might not” are used for non-normative content.</p>
+
   <p>This specification, <em>RDF 1.2 Concepts and Abstract Syntax</em>,
     defines a data model and related terminology for use in
     other specifications, such as