diff --git a/inbox/pubsub-account.xml b/inbox/pubsub-account.xml
index 43b88f48..fd45a4be 100644
--- a/inbox/pubsub-account.xml
+++ b/inbox/pubsub-account.xml
@@ -81,6 +81,11 @@
     <p>Perhaps timing out node types which have not been requested for over a certain period?</p>
     <p>For legacy remote PEP services, the server needs to inject +notify caps into the presence.</p>
     <p>The server also needs to remove +notify caps from legacy clients and spoof traffic?</p>
+    <p>Probably use this to handle point 2 in Device Agility, too.</p>
+    <p>TL;DR: Clients explicitly request a set of nodes (but not domains) that are of interest. I'm calling this the "mask".</p>
+  </section2>
+  <section2 topic='Interaction with MAM' anchor='mam'>
+    <p>We probably want to say that events are now archived by MAM, but this may imply that clients need to filter out such events (or explicitly include them). Maybe the mask above affects MAM queries?</p>
   </section2>
 </section1>
 <section1 topic='Security Considerations' anchor='security'>