--- a/touchevents.html	Fri Jan 28 22:13:56 2011 -0500
+++ b/touchevents.html	Fri Jan 28 22:23:44 2011 -0500
@@ -101,12 +101,25 @@
       <dl title='interface TouchPoint' class='idl'>
         <dt>readonly attribute long identifier</dt>
         <dd>
-          an identification number unique to each touch point, per session
+          An identification number for each touch point, unique to that touch point per session.
+          
+          <p>The algorithm for determining the <a>identifier</a> value is as follows:</p>
+          <ol>
+            <li>if there are no other <a>active touch event session</a>s, the value of <a>identifier</a> must be <code>0</code></li>
+            <li>if there is at least one <a>active touch event session</a>, the value of <a>identifier</a> must be the lowest integer not currently used by any active <a>TouchPoint</a> object in any <a>active touch event session</a></li>
+          </ol> 
         </dd>
         <dt>readonly attribute EventTarget target</dt>
         <dd>
           the original proximal event target for this touch point 
         </dd>
+        <dt>readonly attribute DOMTimeStamp timestamp</dt>
+        <dd>
+          The <a>timestamp</a> attribute represents the time when the <a>TouchPoint</a> was initiated and is represented as a DOMTimeStamp [[!DOM-LEVEL-3-CORE]].
+          <p class="issue" id="issue-timestamp-format"><strong>Issue:</strong> should we align to timestamp as defined in the <a href="http://dev.w3.org/geo/api/#timestamp">Geolocation API spec</a> (as above), or with the datetime as defined in the <a href="http://dev.w3.org/html5/spec/edits.html#attr-mod-datetime">HTML5 spec</a> (attribute DOMString dateTime, where datetime is a <a href="http://dev.w3.org/html5/spec/common-microsyntaxes.html#valid-global-date-and-time-string">valid global date and time string</a>), or to something else (see <a href="http://lists.w3.org/Archives/Public/www-dom/2010OctDec/0069.html">this thread on Event.timeStamp</a>)?</p>
+      
+          <p class="issue" id="issue-timestamp"><strong>Issue:</strong> Should each touchpoint have its own timestamp?  Or should we leave timestamps up to script authors?  My feeling is that having implicit timestamps may be useful in defining an author-defined gesture-like mapping between low-level and high-level events (e.g. a swipe vs. drag speed threshold expressed as the difference in timestamps)</p>
+        </dd>        
 
         <dt>readonly attribute long screenX</dt>
         <dd>
@@ -138,6 +151,7 @@
         <dt>readonly attribute long radiusX</dt>
         <dd>
           the radius of the ellipse which most closely circumscribes the touching area (e.g. finger, stylus) along the x-axis, in pixels of the same scale as <a>screenX</a>; <code>1</code> if no value is known.  This attribute may not be available on all user agents or platforms.
+          <p class="issue" id="issue-units"><strong>Issue:</strong> What are units of radiusX/radiusY?  CSS Pixels?</p>
         </dd>
         <dt>readonly attribute long radiusY</dt>
         <dd>
@@ -147,6 +161,8 @@
         <dt>readonly attribute float force</dt>
         <dd>
           a relative value of pressure applied, in the range <code>0</code> to <code>1</code>, where <code>0</code> is no pressure, and <code>1</code> is the highest level of pressure the touch device is capable of sensing; <code>0</code> if no value is known.  This attribute may not be available on all user agents or platforms.  In environments where <a>force</a> is available, the absolute pressure represented by the <a>force</a> attribute, and the sensitivity in levels of pressure, may vary.
+
+          <p class="issue" id="issue-inkml"><strong>Issue:</strong> Consider aligning with other "channels" and values from <a href="http://www.w3.org/TR/InkML/#channelContents">Ink Markup Language (InkML)</a>, in addition to <a>force</a>, e.g. adding <a>angle</a>, <a>clientZ</a>, <a>rotation</a>, etc.</p>
         </dd>
 
         <dt>readonly attribute boolean altKey</dt>
@@ -163,11 +179,6 @@
         </dd>
       </dl>
       
-      <p class="issue" id="issue-inkml"><strong>Issue:</strong> Consider aligning with "channels" and values from <a href="http://www.w3.org/TR/InkML/#channelContents">Ink Markup Language (InkML)</a>.</p>
-      
-      <p class="issue" id="issue-timestamp"><strong>Issue:</strong> Should each touchpoint have its own timestamp?</p>
-
-      <p class="issue" id="issue-units"><strong>Issue:</strong> What are units of radiusX/radiusY?  CSS Pixels?</p>
     </section>
 
     
@@ -249,6 +260,21 @@
       </section>
     </section>
     
+    <section>
+      <h2>Glossary</h2>
+      
+      <dl>
+        <dt><dfn>active touch event session</dfn></dt>
+        <dd>A conceptual state in which there is at least one instance of a <a>TouchEvent</a> event with at least one non-empty <a>TouchList</a>.
+          <!-- <pre class='example'>
+            
+          </pre> -->
+        </dd>
+        
+      </dl>
+      
+    </section>
+    
     <section class='appendix'>
       <h2>Acknowledgements</h2>
       <p>