diff --git a/resources/sql/autopatches/20160513.owners.01.autoreview.sql b/resources/sql/autopatches/20160513.owners.01.autoreview.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20160513.owners.01.autoreview.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_owners.owners_package
+  ADD autoReview VARCHAR(32) NOT NULL COLLATE {$COLLATE_TEXT};
diff --git a/resources/sql/autopatches/20160513.owners.02.autoreviewnone.sql b/resources/sql/autopatches/20160513.owners.02.autoreviewnone.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20160513.owners.02.autoreviewnone.sql
@@ -0,0 +1,2 @@
+UPDATE {$NAMESPACE}_owners.owners_package
+  SET autoReview = 'none' WHERE autoReview = '';
diff --git a/src/applications/differential/customfield/DifferentialProjectReviewersField.php b/src/applications/differential/customfield/DifferentialProjectReviewersField.php
--- a/src/applications/differential/customfield/DifferentialProjectReviewersField.php
+++ b/src/applications/differential/customfield/DifferentialProjectReviewersField.php
@@ -8,7 +8,7 @@
   }
 
   public function getFieldName() {
-    return pht('Coalition Reviewers');
+    return pht('Group Reviewers');
   }
 
   public function getFieldDescription() {
diff --git a/src/applications/differential/editor/DifferentialTransactionEditor.php b/src/applications/differential/editor/DifferentialTransactionEditor.php
--- a/src/applications/differential/editor/DifferentialTransactionEditor.php
+++ b/src/applications/differential/editor/DifferentialTransactionEditor.php
@@ -7,6 +7,7 @@
   private $isCloseByCommit;
   private $repositoryPHIDOverride = false;
   private $didExpandInlineState = false;
+  private $affectedPaths;
 
   public function getEditorApplicationClass() {
     return 'PhabricatorDifferentialApplication';
@@ -1481,6 +1482,75 @@
     return parent::shouldApplyHeraldRules($object, $xactions);
   }
 
+  protected function didApplyHeraldRules(
+    PhabricatorLiskDAO $object,
+    HeraldAdapter $adapter,
+    HeraldTranscript $transcript) {
+
+    $repository = $object->getRepository();
+    if (!$repository) {
+      return array();
+    }
+
+    if (!$this->affectedPaths) {
+      return array();
+    }
+
+    $packages = PhabricatorOwnersPackage::loadAffectedPackages(
+      $repository,
+      $this->affectedPaths);
+
+    foreach ($packages as $key => $package) {
+      if ($package->isArchived()) {
+        unset($packages[$key]);
+      }
+    }
+
+    if (!$packages) {
+      return array();
+    }
+
+    $auto_subscribe = array();
+    $auto_review = array();
+    $auto_block = array();
+
+    foreach ($packages as $package) {
+      switch ($package->getAutoReview()) {
+        case PhabricatorOwnersPackage::AUTOREVIEW_SUBSCRIBE:
+          $auto_subscribe[] = $package;
+          break;
+        case PhabricatorOwnersPackage::AUTOREVIEW_REVIEW:
+          $auto_review[] = $package;
+          break;
+        case PhabricatorOwnersPackage::AUTOREVIEW_BLOCK:
+          $auto_block[] = $package;
+          break;
+        case PhabricatorOwnersPackage::AUTOREVIEW_NONE:
+        default:
+          break;
+      }
+    }
+
+    $owners_phid = id(new PhabricatorOwnersApplication())
+      ->getPHID();
+
+    $xactions = array();
+    if ($auto_subscribe) {
+
+      $xactions[] = $object->getApplicationTransactionTemplate()
+        ->setAuthorPHID($owners_phid)
+        ->setTransactionType(PhabricatorTransactions::TYPE_SUBSCRIBERS)
+        ->setNewValue(
+          array(
+            '+' => mpull($auto_subscribe, 'getPHID'),
+          ));
+    }
+
+    // TODO: Implement autoreview and autoblock, but these are more invovled.
+
+    return $xactions;
+  }
+
   protected function buildHeraldAdapter(
     PhabricatorLiskDAO $object,
     array $xactions) {
@@ -1557,6 +1627,9 @@
     }
     $all_paths = array_keys($all_paths);
 
+    // Save the affected paths; we'll use them later to query Owners.
+    $this->affectedPaths = $all_paths;
+
     $path_ids =
       PhabricatorRepositoryCommitChangeParserWorker::lookupOrCreatePaths(
         $all_paths);
diff --git a/src/applications/owners/controller/PhabricatorOwnersDetailController.php b/src/applications/owners/controller/PhabricatorOwnersDetailController.php
--- a/src/applications/owners/controller/PhabricatorOwnersDetailController.php
+++ b/src/applications/owners/controller/PhabricatorOwnersDetailController.php
@@ -184,6 +184,12 @@
     }
     $view->addProperty(pht('Owners'), $owner_list);
 
+    $auto = $package->getAutoReview();
+    $autoreview_map = PhabricatorOwnersPackage::getAutoreviewOptionsMap();
+    $spec = idx($autoreview_map, $auto, array());
+    $name = idx($spec, 'name', $auto);
+    $view->addProperty(pht('Auto Review'), $name);
+
     if ($package->getAuditingEnabled()) {
       $auditing = pht('Enabled');
     } else {
diff --git a/src/applications/owners/editor/PhabricatorOwnersPackageEditEngine.php b/src/applications/owners/editor/PhabricatorOwnersPackageEditEngine.php
--- a/src/applications/owners/editor/PhabricatorOwnersPackageEditEngine.php
+++ b/src/applications/owners/editor/PhabricatorOwnersPackageEditEngine.php
@@ -84,6 +84,9 @@
 EOTEXT
       );
 
+    $autoreview_map = PhabricatorOwnersPackage::getAutoreviewOptionsMap();
+    $autoreview_map = ipull($autoreview_map, 'name');
+
     return array(
       id(new PhabricatorTextEditField())
         ->setKey('name')
@@ -101,6 +104,18 @@
         ->setIsCopyable(true)
         ->setValue($object->getOwnerPHIDs()),
       id(new PhabricatorSelectEditField())
+        ->setKey('autoReview')
+        ->setLabel(pht('Auto Review'))
+        ->setDescription(
+          pht(
+            'Automatically trigger reviews for commits affecting files in '.
+            'this package.'))
+        ->setTransactionType(
+          PhabricatorOwnersPackageTransaction::TYPE_AUTOREVIEW)
+        ->setIsCopyable(true)
+        ->setValue($object->getAutoReview())
+        ->setOptions($autoreview_map),
+      id(new PhabricatorSelectEditField())
         ->setKey('auditing')
         ->setLabel(pht('Auditing'))
         ->setDescription(
diff --git a/src/applications/owners/editor/PhabricatorOwnersPackageTransactionEditor.php b/src/applications/owners/editor/PhabricatorOwnersPackageTransactionEditor.php
--- a/src/applications/owners/editor/PhabricatorOwnersPackageTransactionEditor.php
+++ b/src/applications/owners/editor/PhabricatorOwnersPackageTransactionEditor.php
@@ -20,6 +20,7 @@
     $types[] = PhabricatorOwnersPackageTransaction::TYPE_DESCRIPTION;
     $types[] = PhabricatorOwnersPackageTransaction::TYPE_PATHS;
     $types[] = PhabricatorOwnersPackageTransaction::TYPE_STATUS;
+    $types[] = PhabricatorOwnersPackageTransaction::TYPE_AUTOREVIEW;
 
     $types[] = PhabricatorTransactions::TYPE_VIEW_POLICY;
     $types[] = PhabricatorTransactions::TYPE_EDIT_POLICY;
@@ -47,6 +48,8 @@
         return mpull($paths, 'getRef');
       case PhabricatorOwnersPackageTransaction::TYPE_STATUS:
         return $object->getStatus();
+      case PhabricatorOwnersPackageTransaction::TYPE_AUTOREVIEW:
+        return $object->getAutoReview();
     }
   }
 
@@ -58,6 +61,7 @@
       case PhabricatorOwnersPackageTransaction::TYPE_NAME:
       case PhabricatorOwnersPackageTransaction::TYPE_DESCRIPTION:
       case PhabricatorOwnersPackageTransaction::TYPE_STATUS:
+      case PhabricatorOwnersPackageTransaction::TYPE_AUTOREVIEW:
         return $xaction->getNewValue();
       case PhabricatorOwnersPackageTransaction::TYPE_PATHS:
         $new = $xaction->getNewValue();
@@ -113,6 +117,9 @@
       case PhabricatorOwnersPackageTransaction::TYPE_STATUS:
         $object->setStatus($xaction->getNewValue());
         return;
+      case PhabricatorOwnersPackageTransaction::TYPE_AUTOREVIEW:
+        $object->setAutoReview($xaction->getNewValue());
+        return;
     }
 
     return parent::applyCustomInternalTransaction($object, $xaction);
@@ -127,6 +134,7 @@
       case PhabricatorOwnersPackageTransaction::TYPE_DESCRIPTION:
       case PhabricatorOwnersPackageTransaction::TYPE_AUDITING:
       case PhabricatorOwnersPackageTransaction::TYPE_STATUS:
+      case PhabricatorOwnersPackageTransaction::TYPE_AUTOREVIEW:
         return;
       case PhabricatorOwnersPackageTransaction::TYPE_OWNERS:
         $old = $xaction->getOldValue();
@@ -221,6 +229,26 @@
         }
 
         break;
+      case PhabricatorOwnersPackageTransaction::TYPE_AUTOREVIEW:
+        $map = PhabricatorOwnersPackage::getAutoreviewOptionsMap();
+        foreach ($xactions as $xaction) {
+          $new = $xaction->getNewValue();
+
+          if (empty($map[$new])) {
+            $valid = array_keys($map);
+
+            $errors[] = new PhabricatorApplicationTransactionValidationError(
+              $type,
+              pht('Invalid'),
+              pht(
+                'Autoreview setting "%s" is not valid. '.
+                'Valid settings are: %s.',
+                $new,
+                implode(', ', $valid)),
+              $xaction);
+          }
+        }
+        break;
       case PhabricatorOwnersPackageTransaction::TYPE_PATHS:
         if (!$xactions) {
           continue;
diff --git a/src/applications/owners/storage/PhabricatorOwnersPackage.php b/src/applications/owners/storage/PhabricatorOwnersPackage.php
--- a/src/applications/owners/storage/PhabricatorOwnersPackage.php
+++ b/src/applications/owners/storage/PhabricatorOwnersPackage.php
@@ -14,6 +14,7 @@
   protected $name;
   protected $originalName;
   protected $auditingEnabled;
+  protected $autoReview;
   protected $description;
   protected $primaryOwnerPHID;
   protected $mailKey;
@@ -28,6 +29,11 @@
   const STATUS_ACTIVE = 'active';
   const STATUS_ARCHIVED = 'archived';
 
+  const AUTOREVIEW_NONE = 'none';
+  const AUTOREVIEW_SUBSCRIBE = 'subscribe';
+  const AUTOREVIEW_REVIEW = 'review';
+  const AUTOREVIEW_BLOCK = 'block';
+
   public static function initializeNewPackage(PhabricatorUser $actor) {
     $app = id(new PhabricatorApplicationQuery())
       ->setViewer($actor)
@@ -41,6 +47,7 @@
 
     return id(new PhabricatorOwnersPackage())
       ->setAuditingEnabled(0)
+      ->setAutoReview(self::AUTOREVIEW_NONE)
       ->setViewPolicy($view_policy)
       ->setEditPolicy($edit_policy)
       ->attachPaths(array())
@@ -56,6 +63,24 @@
     );
   }
 
+  public static function getAutoreviewOptionsMap() {
+    return array(
+      self::AUTOREVIEW_NONE => array(
+        'name' => pht('No Autoreview'),
+      ),
+      self::AUTOREVIEW_SUBSCRIBE => array(
+        'name' => pht('Subscribe to Changes'),
+      ),
+      // TODO: Implement these.
+      // self::AUTOREVIEW_REVIEW => array(
+      //   'name' => pht('Review Changes'),
+      // ),
+      // self::AUTOREVIEW_BLOCK => array(
+      //   'name' => pht('Review Changes (Blocking)'),
+      // ),
+    );
+  }
+
   protected function getConfiguration() {
     return array(
       // This information is better available from the history table.
@@ -69,6 +94,7 @@
         'auditingEnabled' => 'bool',
         'mailKey' => 'bytes20',
         'status' => 'text32',
+        'autoReview' => 'text32',
       ),
     ) + parent::getConfiguration();
   }
diff --git a/src/applications/owners/storage/PhabricatorOwnersPackageTransaction.php b/src/applications/owners/storage/PhabricatorOwnersPackageTransaction.php
--- a/src/applications/owners/storage/PhabricatorOwnersPackageTransaction.php
+++ b/src/applications/owners/storage/PhabricatorOwnersPackageTransaction.php
@@ -10,6 +10,7 @@
   const TYPE_DESCRIPTION = 'owners.description';
   const TYPE_PATHS = 'owners.paths';
   const TYPE_STATUS = 'owners.status';
+  const TYPE_AUTOREVIEW = 'owners.autoreview';
 
   public function getApplicationName() {
     return 'owners';
@@ -143,6 +144,18 @@
             '%s archived this package.',
             $this->renderHandleLink($author_phid));
         }
+      case self::TYPE_AUTOREVIEW:
+        $map = PhabricatorOwnersPackage::getAutoreviewOptionsMap();
+        $map = ipull($map, 'name');
+
+        $old = idx($map, $old, $old);
+        $new = idx($map, $new, $new);
+
+        return pht(
+          '%s adjusted autoreview from "%s" to "%s".',
+          $this->renderHandleLink($author_phid),
+          $old,
+          $new);
     }
 
     return parent::getTitle();
diff --git a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
--- a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
+++ b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
@@ -703,7 +703,13 @@
       $xaction->setEditPolicy($this->getActingAsPHID());
     }
 
-    $xaction->setAuthorPHID($this->getActingAsPHID());
+    // If the transaction already has an explicit author PHID, allow it to
+    // stand. This is used by applications like Owners that hook into the
+    // post-apply change pipeline.
+    if (!$xaction->getAuthorPHID()) {
+      $xaction->setAuthorPHID($this->getActingAsPHID());
+    }
+
     $xaction->setContentSource($this->getContentSource());
     $xaction->attachViewer($actor);
     $xaction->attachObject($object);
@@ -957,6 +963,12 @@
       if ($herald_xactions) {
         $xscript_id = $this->getHeraldTranscript()->getID();
         foreach ($herald_xactions as $herald_xaction) {
+          // Don't set a transcript ID if this is a transaction from another
+          // application or source, like Owners.
+          if ($herald_xaction->getAuthorPHID()) {
+            continue;
+          }
+
           $herald_xaction->setMetadataValue('herald:transcriptID', $xscript_id);
         }
 
@@ -1217,6 +1229,7 @@
           $xaction,
           pht('You can not apply transactions which already have IDs/PHIDs!'));
       }
+
       if ($xaction->getObjectPHID()) {
         throw new PhabricatorApplicationTransactionStructureException(
           $xaction,
@@ -1224,13 +1237,7 @@
             'You can not apply transactions which already have %s!',
             'objectPHIDs'));
       }
-      if ($xaction->getAuthorPHID()) {
-        throw new PhabricatorApplicationTransactionStructureException(
-          $xaction,
-          pht(
-            'You can not apply transactions which already have %s!',
-            'authorPHIDs'));
-      }
+
       if ($xaction->getCommentPHID()) {
         throw new PhabricatorApplicationTransactionStructureException(
           $xaction,
@@ -1238,6 +1245,7 @@
             'You can not apply transactions which already have %s!',
             'commentPHIDs'));
       }
+
       if ($xaction->getCommentVersion() !== 0) {
         throw new PhabricatorApplicationTransactionStructureException(
           $xaction,