diff --git a/lib/models/room.js b/lib/models/room.js
index 1ba737a8f..9e1d58605 100644
--- a/lib/models/room.js
+++ b/lib/models/room.js
@@ -609,6 +609,7 @@ Room.prototype._addEventToTimeline = function(event, timeline, toStartOfTimeline
  * @private
  */
 Room.prototype._addLiveEvents = function(events) {
+    // var now = Date.now();
     for (var i = 0; i < events.length; i++) {
         if (events[i].getType() === "m.room.redaction") {
             var redactId = events[i].event.redacts;
@@ -652,6 +653,16 @@ Room.prototype._addLiveEvents = function(events) {
             this.addReceipt(synthesizeReceipt(
                 events[i].sender.userId, events[i], "m.read"
             ), true);
+
+            // also, any live events from a user should be taken as implicit
+            // presence information: evidence that they are currently active.
+            // ...except in a world where we use 'user.currentlyActive' to reduce
+            // presence spam, this isn't very useful - we'll get a transition when
+            // they are no longer currently active anyway. so comment it out for now.
+            
+            // var user = this.currentState.getMember(events[i].sender.userId);
+            // user.lastActiveAgo = 0;
+            // user.lastPresenceTs = now;
         }
     }
 };
diff --git a/lib/models/user.js b/lib/models/user.js
index be2b05f2d..152182339 100644
--- a/lib/models/user.js
+++ b/lib/models/user.js
@@ -30,7 +30,12 @@ limitations under the License.
  * @prop {string} displayName The 'displayname' of the user if known.
  * @prop {string} avatarUrl The 'avatar_url' of the user if known.
  * @prop {string} presence The presence enum if known.
- * @prop {Number} lastActiveAgo The last time the user performed some action in ms.
+ * @prop {Number} lastActiveAgo The time elapsed in ms since the user interacted
+ *                proactively with the server, or we saw a message from the user
+ * @prop {Number} lastPresenceTs Timestamp (ms since the epoch) for when we last
+ *                received presence data for this user.  We can subtract
+ *                lastActiveAgo from this to approximate an absolute value for
+ *                when a user was last active.
  * @prop {Boolean} currentlyActive Whether we should consider lastActiveAgo to be
  *               an approximation and that the user should be seen as active 'now'
  * @prop {Object} events The events describing this user.
@@ -42,6 +47,7 @@ function User(userId) {
     this.displayName = userId;
     this.avatarUrl = null;
     this.lastActiveAgo = 0;
+    this.lastPresenceTs = 0;
     this.currentlyActive = false;
     this.events = {
         presence: null,
@@ -82,6 +88,7 @@ User.prototype.setPresenceEvent = function(event) {
     this.displayName = event.getContent().displayname;
     this.avatarUrl = event.getContent().avatar_url;
     this.lastActiveAgo = event.getContent().last_active_ago;
+    this.lastPresenceTs = Date.now();
     this.currentlyActive = event.getContent().currently_active;
 
     if (eventsToFire.length > 0) {