Index: src/applications/differential/editor/DifferentialCommentEditor.php
===================================================================
--- src/applications/differential/editor/DifferentialCommentEditor.php
+++ src/applications/differential/editor/DifferentialCommentEditor.php
@@ -647,7 +647,7 @@
       $mail = id(new DifferentialCommentMail(
         $revision,
         $actor_handle,
-        $comment,
+        array($comment),
         $changesets,
         $inline_comments))
         ->setActor($actor)
Index: src/applications/differential/editor/DifferentialRevisionEditor.php
===================================================================
--- src/applications/differential/editor/DifferentialRevisionEditor.php
+++ src/applications/differential/editor/DifferentialRevisionEditor.php
@@ -381,24 +381,21 @@
     $actor_handle = $handles[$this->getActorPHID()];
 
     $changesets = null;
-    $comment = null;
     $old_status = $revision->getStatus();
 
     if ($diff) {
       $changesets = $diff->loadChangesets();
       // TODO: This should probably be in DifferentialFeedbackEditor?
       if (!$is_new) {
-        $comment = $this->createComment();
-      }
-      if ($comment) {
+        $this->createComment();
         $mail[] = id(new DifferentialNewDiffMail(
             $revision,
             $actor_handle,
             $changesets))
           ->setActor($this->getActor())
-          ->setIsFirstMailAboutRevision($is_new)
-          ->setIsFirstMailToRecipients($is_new)
-          ->setComments($this->getComments())
+          ->setIsFirstMailAboutRevision(false)
+          ->setIsFirstMailToRecipients(false)
+          ->setCommentText($this->getComments())
           ->setToPHIDs(array_keys($stable['rev']))
           ->setCCPHIDs(array_keys($stable['ccs']));
       }
@@ -804,8 +801,6 @@
     }
 
     $comment->save();
-
-    return $comment;
   }
 
   private function updateAuxiliaryFields() {
Index: src/applications/differential/mail/DifferentialCommentMail.php
===================================================================
--- src/applications/differential/mail/DifferentialCommentMail.php
+++ src/applications/differential/mail/DifferentialCommentMail.php
@@ -19,56 +19,60 @@
   public function __construct(
     DifferentialRevision $revision,
     PhabricatorObjectHandle $actor,
-    DifferentialComment $comment,
+    array $comments,
     array $changesets,
     array $inline_comments) {
+
+    assert_instances_of($comments, 'DifferentialComment');
     assert_instances_of($changesets, 'DifferentialChangeset');
     assert_instances_of($inline_comments, 'PhabricatorInlineCommentInterface');
 
     $this->setRevision($revision);
     $this->setActorHandle($actor);
-    $this->setComment($comment);
+    $this->setComments($comments);
     $this->setChangesets($changesets);
     $this->setInlineComments($inline_comments);
 
   }
 
   protected function getMailTags() {
-    $tags    = array();
-    $comment = $this->getComment();
-    $action  = $comment->getAction();
-
-    switch ($action) {
-      case DifferentialAction::ACTION_ADDCCS:
-        $tags[] = MetaMTANotificationType::TYPE_DIFFERENTIAL_CC;
-        break;
-      case DifferentialAction::ACTION_CLOSE:
-        $tags[] = MetaMTANotificationType::TYPE_DIFFERENTIAL_CLOSED;
-        break;
-      case DifferentialAction::ACTION_ADDREVIEWERS:
-        $tags[] = MetaMTANotificationType::TYPE_DIFFERENTIAL_REVIEWERS;
-        break;
-      case DifferentialAction::ACTION_COMMENT:
-        // this is a comment which we will check separately below for content
-        break;
-      default:
-        $tags[] = MetaMTANotificationType::TYPE_DIFFERENTIAL_OTHER;
-        break;
-    }
+    $tags = array();
 
-    $has_comment = strlen(trim($comment->getContent()));
-    $has_inlines = (bool)$this->getInlineComments();
+    foreach ($this->getComments() as $comment) {
+      $action = $comment->getAction();
 
-    if ($has_comment || $has_inlines) {
       switch ($action) {
+        case DifferentialAction::ACTION_ADDCCS:
+          $tags[] = MetaMTANotificationType::TYPE_DIFFERENTIAL_CC;
+          break;
         case DifferentialAction::ACTION_CLOSE:
-          // Commit comments are auto-generated and not especially interesting,
-          // so don't tag them as having a comment.
+          $tags[] = MetaMTANotificationType::TYPE_DIFFERENTIAL_CLOSED;
+          break;
+        case DifferentialAction::ACTION_ADDREVIEWERS:
+          $tags[] = MetaMTANotificationType::TYPE_DIFFERENTIAL_REVIEWERS;
+          break;
+        case DifferentialAction::ACTION_COMMENT:
+          // this is a comment which we will check separately below for content
           break;
         default:
-          $tags[] = MetaMTANotificationType::TYPE_DIFFERENTIAL_COMMENT;
+          $tags[] = MetaMTANotificationType::TYPE_DIFFERENTIAL_OTHER;
           break;
       }
+
+      $has_comment = strlen(trim($comment->getContent()));
+      $has_inlines = (bool)$this->getInlineComments();
+
+      if ($has_comment || $has_inlines) {
+        switch ($action) {
+          case DifferentialAction::ACTION_CLOSE:
+            // Commit comments are auto-generated and not especially
+            // interesting, so don't tag them as having a comment.
+            break;
+          default:
+            $tags[] = MetaMTANotificationType::TYPE_DIFFERENTIAL_COMMENT;
+            break;
+        }
+      }
     }
 
     if (!$tags) {
@@ -84,7 +88,9 @@
   }
 
   protected function getVerb() {
-    $comment = $this->getComment();
+    // NOTE: Eventually, this will use getStrongestAction() transaction logic.
+    // For now, pick the first comment.
+    $comment = head($this->getComments());
     $action = $comment->getAction();
     $verb = DifferentialAction::getActionPastTenseVerb($action);
     return $verb;
@@ -94,16 +100,22 @@
     parent::prepareBody();
 
     // If the commented added reviewers or CCs, list them explicitly.
-    $meta = $this->getComment()->getMetadata();
-    $m_reviewers = idx(
-      $meta,
-      DifferentialComment::METADATA_ADDED_REVIEWERS,
-      array());
-    $m_cc = idx(
-      $meta,
-      DifferentialComment::METADATA_ADDED_CCS,
-      array());
-    $load = array_merge($m_reviewers, $m_cc);
+    $load = array();
+    foreach ($this->comments as $comment) {
+      $meta = $comment->getMetadata();
+      $m_reviewers = idx(
+        $meta,
+        DifferentialComment::METADATA_ADDED_REVIEWERS,
+        array());
+      $m_cc = idx(
+        $meta,
+        DifferentialComment::METADATA_ADDED_CCS,
+        array());
+      $load[] = $m_reviewers;
+      $load[] = $m_cc;
+    }
+
+    $load = array_mergev($load);
     if ($load) {
       $handles = id(new PhabricatorHandleQuery())
         ->setViewer($this->getActor())
@@ -119,8 +131,10 @@
   }
 
   protected function renderBody() {
+    // TODO: This will be ApplicationTransactions eventually, but split the
+    // difference for now.
 
-    $comment = $this->getComment();
+    $comment = head($this->getComments());
 
     $actor = $this->getActorName();
     $name  = $this->getRevision()->getTitle();
@@ -139,10 +153,12 @@
 
     $body[] = null;
 
-    $content = $comment->getContent();
-    if (strlen($content)) {
-      $body[] = $this->formatText($content);
-      $body[] = null;
+    foreach ($this->getComments() as $comment) {
+      $content = $comment->getContent();
+      if (strlen($content)) {
+        $body[] = $this->formatText($content);
+        $body[] = null;
+      }
     }
 
     if ($this->getChangedByCommit()) {
Index: src/applications/differential/mail/DifferentialMail.php
===================================================================
--- src/applications/differential/mail/DifferentialMail.php
+++ src/applications/differential/mail/DifferentialMail.php
@@ -9,7 +9,7 @@
   protected $actorHandle;
 
   protected $revision;
-  protected $comment;
+  protected $comments;
   protected $changesets;
   protected $inlineComments;
   protected $isFirstMailAboutRevision;
@@ -370,13 +370,13 @@
     return "D{$id}: {$title}";
   }
 
-  public function setComment($comment) {
-    $this->comment = $comment;
+  public function setComments(array $comments) {
+    $this->comments = $comments;
     return $this;
   }
 
-  public function getComment() {
-    return $this->comment;
+  public function getComments() {
+    return $this->comments;
   }
 
   public function setChangesets($changesets) {
Index: src/applications/differential/mail/DifferentialReviewRequestMail.php
===================================================================
--- src/applications/differential/mail/DifferentialReviewRequestMail.php
+++ src/applications/differential/mail/DifferentialReviewRequestMail.php
@@ -4,17 +4,17 @@
 
   const MAX_AFFECTED_FILES = 1000;
 
-  protected $comments;
+  protected $commentText;
 
   private $patch;
 
-  public function setComments($comments) {
-    $this->comments = $comments;
+  public function setCommentText($comment_text) {
+    $this->commentText = $comment_text;
     return $this;
   }
 
-  public function getComments() {
-    return $this->comments;
+  public function getCommentText() {
+    return $this->commentText;
   }
 
   public function __construct(
@@ -46,8 +46,8 @@
 
     $body = array();
     if (!$this->isFirstMailToRecipients()) {
-      if (strlen($this->getComments())) {
-        $body[] = $this->formatText($this->getComments());
+      if (strlen($this->getCommentText())) {
+        $body[] = $this->formatText($this->getCommentText());
         $body[] = null;
       }
     }