diff --git a/resources/sql/patches/042.commentmetadata.sql b/resources/sql/patches/042.commentmetadata.sql
new file mode 100644
index 0000000000..1b27799732
--- /dev/null
+++ b/resources/sql/patches/042.commentmetadata.sql
@@ -0,0 +1,11 @@
+ALTER TABLE phabricator_differential.differential_comment
+  ADD metadata LONGBLOB NOT NULL;
+
+UPDATE phabricator_differential.differential_comment
+  SET metadata = '{}' WHERE metadata = '';
+
+ALTER TABLE phabricator_maniphest.maniphest_transaction
+  ADD metadata LONGBLOB NOT NULL;
+
+UPDATE phabricator_maniphest.maniphest_transaction
+  SET metadata = '{}' WHERE metadata = '';
diff --git a/src/applications/differential/controller/revisionview/DifferentialRevisionViewController.php b/src/applications/differential/controller/revisionview/DifferentialRevisionViewController.php
index 6fee204b02..f9b4a7748f 100644
--- a/src/applications/differential/controller/revisionview/DifferentialRevisionViewController.php
+++ b/src/applications/differential/controller/revisionview/DifferentialRevisionViewController.php
@@ -78,6 +78,19 @@ class DifferentialRevisionViewController extends DifferentialController {
         $user->getPHID(),
       ),
       mpull($comments, 'getAuthorPHID'));
+
+    foreach ($comments as $comment) {
+      $metadata = $comment->getMetadata();
+      $added_reviewers = idx(
+        $metadata,
+        DifferentialComment::METADATA_ADDED_REVIEWERS);
+      if ($added_reviewers) {
+        foreach ($added_reviewers as $phid) {
+          $object_phids[] = $phid;
+        }
+      }
+    }
+
     foreach ($revision->getAttached() as $type => $phids) {
       foreach ($phids as $phid => $info) {
         $object_phids[] = $phid;
diff --git a/src/applications/differential/editor/comment/DifferentialCommentEditor.php b/src/applications/differential/editor/comment/DifferentialCommentEditor.php
index 7fb98ee6c4..03a919f96b 100644
--- a/src/applications/differential/editor/comment/DifferentialCommentEditor.php
+++ b/src/applications/differential/editor/comment/DifferentialCommentEditor.php
@@ -84,6 +84,8 @@ class DifferentialCommentEditor {
       $reviewer_phids = array_combine($reviewer_phids, $reviewer_phids);
     }
 
+    $metadata = array();
+
     switch ($action) {
       case DifferentialAction::ACTION_COMMENT:
         break;
@@ -242,13 +244,8 @@ class DifferentialCommentEditor {
             $add = $added_reviewers,
             $actor_phid);
 
-          $handles = id(new PhabricatorObjectHandleData($added_reviewers))
-            ->loadHandles();
-          $usernames = mpull($handles, 'getName');
-
-          $this->message =
-            'Added reviewers: '.implode(', ', $usernames)."\n\n".
-            $this->message;
+          $key = DifferentialComment::METADATA_ADDED_REVIEWERS;
+          $metadata[$key] = $added_reviewers;
 
         } else {
           $action = DifferentialAction::ACTION_COMMENT;
@@ -282,6 +279,7 @@ class DifferentialCommentEditor {
       ->setRevisionID($revision->getID())
       ->setAction($action)
       ->setContent((string)$this->message)
+      ->setMetadata($metadata)
       ->save();
 
     $changesets = array();
diff --git a/src/applications/differential/storage/comment/DifferentialComment.php b/src/applications/differential/storage/comment/DifferentialComment.php
index 1349ddc772..8eebf0afe3 100644
--- a/src/applications/differential/storage/comment/DifferentialComment.php
+++ b/src/applications/differential/storage/comment/DifferentialComment.php
@@ -18,10 +18,21 @@
 
 class DifferentialComment extends DifferentialDAO {
 
+  const METADATA_ADDED_REVIEWERS = 'added-reviewers';
+
   protected $authorPHID;
   protected $revisionID;
   protected $action;
   protected $content;
   protected $cache;
+  protected $metadata = array();
+
+  public function getConfiguration() {
+    return array(
+      self::CONFIG_SERIALIZATION => array(
+        'metadata' => self::SERIALIZATION_JSON,
+      ),
+    ) + parent::getConfiguration();
+  }
 
 }
diff --git a/src/applications/differential/view/revisioncomment/DifferentialRevisionCommentView.php b/src/applications/differential/view/revisioncomment/DifferentialRevisionCommentView.php
index 62e710be47..73f07f0973 100644
--- a/src/applications/differential/view/revisioncomment/DifferentialRevisionCommentView.php
+++ b/src/applications/differential/view/revisioncomment/DifferentialRevisionCommentView.php
@@ -109,6 +109,7 @@ final class DifferentialRevisionCommentView extends AphrontView {
     $verb = phutil_escape_html($verb);
 
     $content = $comment->getContent();
+    $head_content = null;
     if (strlen(rtrim($content))) {
       $title = "{$author_link} {$verb} this revision:";
       $cache = $comment->getCache();
@@ -127,10 +128,11 @@ final class DifferentialRevisionCommentView extends AphrontView {
         '</div>';
     } else {
       $title = null;
-      $content =
+      $head_content =
         '<div class="differential-comment-nocontent">'.
           "<p>{$author_link} {$verb} this revision.</p>".
         '</div>';
+      $content = null;
     }
 
     if ($this->inlines) {
@@ -213,6 +215,29 @@ final class DifferentialRevisionCommentView extends AphrontView {
       $background = "background-image: url('{$uri}');";
     }
 
+    $metadata_blocks = array();
+    $metadata = $comment->getMetadata();
+    $added_reviewers = idx(
+      $metadata,
+      DifferentialComment::METADATA_ADDED_REVIEWERS);
+    if ($added_reviewers) {
+      $reviewers = array();
+      foreach ($added_reviewers as $phid) {
+        $reviewers[] = $this->handles[$phid]->renderLink();
+      }
+      $reviewers = 'Added reviewers: '.implode(', ', $reviewers);
+      $metadata_blocks[] = $reviewers;
+    }
+
+    if ($metadata_blocks) {
+      $metadata_blocks =
+        '<div class="differential-comment-metadata">'.
+          implode("\n", $metadata_blocks).
+        '</div>';
+    } else {
+      $metadata_blocks = null;
+    }
+
     return phutil_render_tag(
       'div',
       array(
@@ -226,6 +251,8 @@ final class DifferentialRevisionCommentView extends AphrontView {
       '</div>'.
       '<div class="differential-comment-body" style="'.$background.'">'.
         '<div class="differential-comment-content">'.
+          $head_content.
+          $metadata_blocks.
           '<div class="differential-comment-core">'.
             $content.
           '</div>'.
diff --git a/src/applications/differential/view/revisioncomment/__init__.php b/src/applications/differential/view/revisioncomment/__init__.php
index e4667c0379..d240fa85ca 100644
--- a/src/applications/differential/view/revisioncomment/__init__.php
+++ b/src/applications/differential/view/revisioncomment/__init__.php
@@ -7,6 +7,7 @@
 
 
 phutil_require_module('phabricator', 'applications/differential/constants/action');
+phutil_require_module('phabricator', 'applications/differential/storage/comment');
 phutil_require_module('phabricator', 'infrastructure/celerity/api');
 phutil_require_module('phabricator', 'infrastructure/javelin/api');
 phutil_require_module('phabricator', 'view/base');
diff --git a/src/applications/maniphest/storage/transaction/ManiphestTransaction.php b/src/applications/maniphest/storage/transaction/ManiphestTransaction.php
index 191ac6f0f5..ba7e5bf2ec 100644
--- a/src/applications/maniphest/storage/transaction/ManiphestTransaction.php
+++ b/src/applications/maniphest/storage/transaction/ManiphestTransaction.php
@@ -25,12 +25,14 @@ class ManiphestTransaction extends ManiphestDAO {
   protected $newValue;
   protected $comments;
   protected $cache;
+  protected $metadata = array();
 
   public function getConfiguration() {
     return array(
       self::CONFIG_SERIALIZATION => array(
         'oldValue' => self::SERIALIZATION_JSON,
         'newValue' => self::SERIALIZATION_JSON,
+        'metadata' => self::SERIALIZATION_JSON,
       ),
     ) + parent::getConfiguration();
   }