Add privacy-focused topic (#8)

See discussion in:
w3c/strategy#205 (comment)

index.html

@@ -242,6 +242,13 @@ <h2>
               <b>Metadata creation and management</b> in production workflows,
               including metadata about content provenance and authenticity.
             </li>
+            <li>
+              With the awareness that tracking, attribution, and authenticity
+              proofs, as above, can pose privacy harms, particularly outside of
+              professional use cases, mechanisms for limiting their use outside
+              of professional contexts, making it clear when they're in use, and
+              making them opt-in.
+            </li>
             <li>
               <b>Compatibility with legacy systems</b> and standards, e.g.
               timecode.