diff --git a/resources/celerity/map.php b/resources/celerity/map.php
index 32161243de..7df620a718 100644
--- a/resources/celerity/map.php
+++ b/resources/celerity/map.php
@@ -125,7 +125,7 @@ return array(
     'rsrc/css/phui/phui-box.css' => '7b3a2eed',
     'rsrc/css/phui/phui-button.css' => 'c7412aa1',
     'rsrc/css/phui/phui-document.css' => 'a5615198',
-    'rsrc/css/phui/phui-feed-story.css' => 'e2c9bc83',
+    'rsrc/css/phui/phui-feed-story.css' => '55dc7732',
     'rsrc/css/phui/phui-fontkit.css' => 'fff25cfa',
     'rsrc/css/phui/phui-form-view.css' => 'a2d72756',
     'rsrc/css/phui/phui-form.css' => 'b78ec020',
@@ -771,7 +771,7 @@ return array(
     'phui-calendar-list-css' => 'c1d0ca59',
     'phui-calendar-month-css' => 'a92e47d2',
     'phui-document-view-css' => 'a5615198',
-    'phui-feed-story-css' => 'e2c9bc83',
+    'phui-feed-story-css' => '55dc7732',
     'phui-font-icon-base-css' => 'eb84f033',
     'phui-fontkit-css' => 'fff25cfa',
     'phui-form-css' => 'b78ec020',
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index 66587a7b07..8f5b7d061a 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -4376,7 +4376,10 @@ phutil_register_library_map(array(
     'PhabricatorFeedPublicStreamController' => 'PhabricatorFeedController',
     'PhabricatorFeedQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
     'PhabricatorFeedSearchEngine' => 'PhabricatorApplicationSearchEngine',
-    'PhabricatorFeedStory' => 'PhabricatorPolicyInterface',
+    'PhabricatorFeedStory' => array(
+      'PhabricatorPolicyInterface',
+      'PhabricatorMarkupInterface',
+    ),
     'PhabricatorFeedStoryAggregate' => 'PhabricatorFeedStory',
     'PhabricatorFeedStoryAudit' => 'PhabricatorFeedStory',
     'PhabricatorFeedStoryCommit' => 'PhabricatorFeedStory',
diff --git a/src/applications/feed/story/PhabricatorFeedStory.php b/src/applications/feed/story/PhabricatorFeedStory.php
index 4ee8a6372f..04d5b7fd75 100644
--- a/src/applications/feed/story/PhabricatorFeedStory.php
+++ b/src/applications/feed/story/PhabricatorFeedStory.php
@@ -8,7 +8,10 @@
  * @task load     Loading Stories
  * @task policy   Policy Implementation
  */
-abstract class PhabricatorFeedStory implements PhabricatorPolicyInterface {
+abstract class PhabricatorFeedStory
+  implements
+    PhabricatorPolicyInterface,
+    PhabricatorMarkupInterface {
 
   private $data;
   private $hasViewed;
@@ -19,6 +22,7 @@ abstract class PhabricatorFeedStory implements PhabricatorPolicyInterface {
   private $handles = array();
   private $objects = array();
   private $projectPHIDs = array();
+  private $markupFieldOutput = array();
 
 /* -(  Loading Stories  )---------------------------------------------------- */
 
@@ -150,9 +154,46 @@ abstract class PhabricatorFeedStory implements PhabricatorPolicyInterface {
       $stories[$key]->setHandles($story_handles);
     }
 
+    // Load and process story markup blocks.
+
+    $engine = new PhabricatorMarkupEngine();
+    $engine->setViewer($viewer);
+    foreach ($stories as $story) {
+      foreach ($story->getFieldStoryMarkupFields() as $field) {
+        $engine->addObject($story, $field);
+      }
+    }
+
+    $engine->process();
+
+    foreach ($stories as $story) {
+      foreach ($story->getFieldStoryMarkupFields() as $field) {
+        $story->setMarkupFieldOutput(
+          $field,
+          $engine->getOutput($story, $field));
+      }
+    }
+
     return $stories;
   }
 
+  public function setMarkupFieldOutput($field, $output) {
+    $this->markupFieldOutput[$field] = $output;
+    return $this;
+  }
+
+  public function getMarkupFieldOutput($field) {
+    if (!array_key_exists($field, $this->markupFieldOutput)) {
+      throw new Exception(
+        pht(
+          'Trying to retrieve markup field key "%s", but this feed story '.
+          'did not request it be rendered.',
+          $field));
+    }
+
+    return $this->markupFieldOutput[$field];
+  }
+
   public function setHovercard($hover) {
     $this->hovercard = $hover;
     return $this;
@@ -374,6 +415,10 @@ abstract class PhabricatorFeedStory implements PhabricatorPolicyInterface {
     return $this->projectPHIDs;
   }
 
+  public function getFieldStoryMarkupFields() {
+    return array();
+  }
+
 
 /* -(  PhabricatorPolicyInterface Implementation  )-------------------------- */
 
@@ -425,4 +470,31 @@ abstract class PhabricatorFeedStory implements PhabricatorPolicyInterface {
     return null;
   }
 
+
+/* -(  PhabricatorMarkupInterface Implementation )--------------------------- */
+
+
+  public function getMarkupFieldKey($field) {
+    return 'feed:'.$this->getChronologicalKey().':'.$field;
+  }
+
+  public function newMarkupEngine($field) {
+    return PhabricatorMarkupEngine::newMarkupEngine(array());
+  }
+
+  public function getMarkupText($field) {
+    throw new PhutilMethodNotImplementedException();
+  }
+
+  public function didMarkupText(
+    $field,
+    $output,
+    PhutilMarkupEngine $engine) {
+    return $output;
+  }
+
+  public function shouldUseMarkupCache($field) {
+    return true;
+  }
+
 }
diff --git a/src/applications/transactions/feed/PhabricatorApplicationTransactionFeedStory.php b/src/applications/transactions/feed/PhabricatorApplicationTransactionFeedStory.php
index dc820fb6db..0e488b359a 100644
--- a/src/applications/transactions/feed/PhabricatorApplicationTransactionFeedStory.php
+++ b/src/applications/transactions/feed/PhabricatorApplicationTransactionFeedStory.php
@@ -34,6 +34,35 @@ class PhabricatorApplicationTransactionFeedStory
     return $this->getObject($this->getPrimaryTransactionPHID());
   }
 
+  public function getFieldStoryMarkupFields() {
+    $xaction_phids = $this->getValue('transactionPHIDs');
+
+    $fields = array();
+    foreach ($xaction_phids as $xaction_phid) {
+      $xaction = $this->getObject($xaction_phid);
+      foreach ($xaction->getMarkupFieldsForFeed($this) as $field) {
+        $fields[] = $field;
+      }
+    }
+
+    return $fields;
+  }
+
+  public function getMarkupText($field) {
+    $xaction_phids = $this->getValue('transactionPHIDs');
+
+    foreach ($xaction_phids as $xaction_phid) {
+      $xaction = $this->getObject($xaction_phid);
+      foreach ($xaction->getMarkupFieldsForFeed($this) as $xaction_field) {
+        if ($xaction_field == $field) {
+          return $xaction->getMarkupTextForFeed($this, $field);
+        }
+      }
+    }
+
+    return null;
+  }
+
   public function renderView() {
     $view = $this->newStoryView();
 
diff --git a/src/applications/transactions/storage/PhabricatorApplicationTransaction.php b/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
index c5cbe2e72f..103d894309 100644
--- a/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
+++ b/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
@@ -788,6 +788,31 @@ abstract class PhabricatorApplicationTransaction
     return $this->getTitle();
   }
 
+  public function getMarkupFieldsForFeed(PhabricatorFeedStory $story) {
+    $fields = array();
+
+    switch ($this->getTransactionType()) {
+      case PhabricatorTransactions::TYPE_COMMENT:
+        $text = $this->getComment()->getContent();
+        if (strlen($text)) {
+          $fields[] = 'comment/'.$this->getID();
+        }
+        break;
+    }
+
+    return $fields;
+  }
+
+  public function getMarkupTextForFeed(PhabricatorFeedStory $story, $field) {
+    switch ($this->getTransactionType()) {
+      case PhabricatorTransactions::TYPE_COMMENT:
+        $text = $this->getComment()->getContent();
+        return PhabricatorMarkupEngine::summarize($text);
+    }
+
+    return null;
+  }
+
   public function getBodyForFeed(PhabricatorFeedStory $story) {
     $old = $this->getOldValue();
     $new = $this->getNewValue();
@@ -797,10 +822,12 @@ abstract class PhabricatorApplicationTransaction
     switch ($this->getTransactionType()) {
       case PhabricatorTransactions::TYPE_COMMENT:
         $text = $this->getComment()->getContent();
-        $body = phutil_escape_html_newlines(
-          phutil_utf8_shorten($text, 128));
+        if (strlen($text)) {
+          $body = $story->getMarkupFieldOutput('comment/'.$this->getID());
+        }
         break;
     }
+
     return $body;
   }
 
diff --git a/src/infrastructure/markup/rule/PhabricatorNavigationRemarkupRule.php b/src/infrastructure/markup/rule/PhabricatorNavigationRemarkupRule.php
index cef6f22b00..d0bf3a69b1 100644
--- a/src/infrastructure/markup/rule/PhabricatorNavigationRemarkupRule.php
+++ b/src/infrastructure/markup/rule/PhabricatorNavigationRemarkupRule.php
@@ -8,7 +8,7 @@ final class PhabricatorNavigationRemarkupRule extends PhutilRemarkupRule {
 
   public function apply($text) {
     return preg_replace_callback(
-      '@{nav\b((?:[^}\\\\]+|\\\\.)+)}$@m',
+      '@{nav\b((?:[^}\\\\]+|\\\\.)*)}@m',
       array($this, 'markupNavigation'),
       $text);
   }
@@ -99,5 +99,4 @@ final class PhabricatorNavigationRemarkupRule extends PhutilRemarkupRule {
     return $this->getEngine()->storeText($out);
   }
 
-
 }
diff --git a/webroot/rsrc/css/phui/phui-feed-story.css b/webroot/rsrc/css/phui/phui-feed-story.css
index 2749566ee5..f53a2dcbf9 100644
--- a/webroot/rsrc/css/phui/phui-feed-story.css
+++ b/webroot/rsrc/css/phui/phui-feed-story.css
@@ -28,9 +28,11 @@
 }
 
 .phui-feed-story-body {
-  padding: 0 8px 8px;
+  margin: 0 8px 8px;
   color: {$darkgreytext};
   word-break: break-word;
+  max-height: 300px;
+  overflow: hidden;
 }
 
 .phui-feed-story-foot {