The most important feature

src/molecules/MessageComposer.js

@@ -6,10 +6,21 @@ module.exports = React.createClass({
     onKeyDown: function (ev) {
         if (ev.keyCode == 13) {
             var contentText = this.refs.textarea.getDOMNode().value;
-            MatrixClientPeg.get().sendMessage(this.props.roomId, {
-                msgtype: 'm.text',
-                body: contentText
-            });
+
+            var content = null;
+            if (/^\/me /i.test(contentText)) {
+                content = {
+                    msgtype: 'm.emote',
+                    body: contentText.substring(4)
+                };
+            } else {
+                content = {
+                    msgtype: 'm.text',
+                    body: contentText
+                };
+            }
+
+            MatrixClientPeg.get().sendMessage(this.props.roomId, content);
             this.refs.textarea.getDOMNode().value = '';
             ev.preventDefault();
         }

src/molecules/MessageTile.js

@@ -6,7 +6,8 @@ var SenderProfile = require('../molecules/SenderProfile');
 var UnknownMessageTile = require('../molecules/UnknownMessageTile');
 
 var tileTypes = {
-    'm.text': require('../molecules/MTextTile')
+    'm.text': require('../molecules/MTextTile'),
+    'm.emote': require('../molecules/MEmoteTile')
 };
 
 module.exports = React.createClass({

src/molecules/SenderProfile.js

@@ -4,6 +4,11 @@ module.exports = React.createClass({
     render: function() {
         var mxEvent = this.props.mxEvent;
         var name = mxEvent.sender ? mxEvent.sender.name : mxEvent.getSender();
+
+        var msgtype = mxEvent.getContent().msgtype;
+        if (msgtype && msgtype == 'm.emote') {
+            name = ''; // emote message must include the name so don't duplicate it
+        }
         return (
             <span className="mx_SenderProfile">
                 {name}