diff --git a/resources/sql/patches/20130820.file-mailkey-populate.php b/resources/sql/patches/20130820.file-mailkey-populate.php
new file mode 100644
index 0000000000..f1d2a22a92
--- /dev/null
+++ b/resources/sql/patches/20130820.file-mailkey-populate.php
@@ -0,0 +1,32 @@
+<?php
+
+echo "Populating Phabricator files with mail keys xactions...\n";
+
+$table = new PhabricatorFile();
+$table_name = $table->getTableName();
+
+$conn_w = $table->establishConnection('w');
+$conn_w->openTransaction();
+
+$sql = array();
+foreach (new LiskRawMigrationIterator($conn_w, 'file') as $row) {
+  $sql[] = qsprintf(
+    $conn_w,
+    '(%d, %s)',
+    $row['id'],
+    Filesystem::readRandomCharacters(20));
+}
+
+if ($sql) {
+  foreach (PhabricatorLiskDAO::chunkSQL($sql, ', ') as $chunk) {
+    queryfx(
+      $conn_w,
+      'INSERT INTO %T (id, mailKey) VALUES %Q '.
+      'ON DUPLICATE KEY UPDATE mailKey = VALUES(mailKey)',
+      $table_name,
+      $chunk);
+  }
+}
+
+$table->saveTransaction();
+echo "Done.\n";
diff --git a/resources/sql/patches/20130820.filemailkey.sql b/resources/sql/patches/20130820.filemailkey.sql
new file mode 100644
index 0000000000..7daa46a609
--- /dev/null
+++ b/resources/sql/patches/20130820.filemailkey.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_file.file
+  ADD `mailKey` varchar(20) NOT NULL;
diff --git a/resources/sql/patches/20130820.filexactions.sql b/resources/sql/patches/20130820.filexactions.sql
new file mode 100644
index 0000000000..8f92df563f
--- /dev/null
+++ b/resources/sql/patches/20130820.filexactions.sql
@@ -0,0 +1,42 @@
+CREATE TABLE {$NAMESPACE}_file.file_transaction (
+  id INT UNSIGNED NOT NULL PRIMARY KEY AUTO_INCREMENT,
+  phid VARCHAR(64) NOT NULL COLLATE utf8_bin,
+  authorPHID VARCHAR(64) NOT NULL COLLATE utf8_bin,
+  objectPHID VARCHAR(64) NOT NULL COLLATE utf8_bin,
+  viewPolicy VARCHAR(64) NOT NULL COLLATE utf8_bin,
+  editPolicy VARCHAR(64) NOT NULL COLLATE utf8_bin,
+  commentPHID VARCHAR(64) COLLATE utf8_bin,
+  commentVersion INT UNSIGNED NOT NULL,
+  transactionType VARCHAR(32) NOT NULL COLLATE utf8_bin,
+  oldValue LONGTEXT NOT NULL COLLATE utf8_bin,
+  newValue LONGTEXT NOT NULL COLLATE utf8_bin,
+  contentSource LONGTEXT NOT NULL COLLATE utf8_bin,
+  metadata LONGTEXT NOT NULL COLLATE utf8_bin,
+  dateCreated INT UNSIGNED NOT NULL,
+  dateModified INT UNSIGNED NOT NULL,
+
+  UNIQUE KEY `key_phid` (phid),
+  KEY `key_object` (objectPHID)
+
+) ENGINE=InnoDB, COLLATE utf8_general_ci;
+
+CREATE TABLE {$NAMESPACE}_file.file_transaction_comment (
+  id INT UNSIGNED NOT NULL PRIMARY KEY AUTO_INCREMENT,
+  phid VARCHAR(64) NOT NULL COLLATE utf8_bin,
+  transactionPHID VARCHAR(64) COLLATE utf8_bin,
+  authorPHID VARCHAR(64) NOT NULL COLLATE utf8_bin,
+  viewPolicy VARCHAR(64) NOT NULL COLLATE utf8_bin,
+  editPolicy VARCHAR(64) NOT NULL COLLATE utf8_bin,
+  commentVersion INT UNSIGNED NOT NULL,
+  content LONGTEXT NOT NULL COLLATE utf8_bin,
+  contentSource LONGTEXT NOT NULL COLLATE utf8_bin,
+  isDeleted BOOL NOT NULL,
+  dateCreated INT UNSIGNED NOT NULL,
+  dateModified INT UNSIGNED NOT NULL,
+
+  UNIQUE KEY `key_phid` (phid),
+  UNIQUE KEY `key_version` (transactionPHID, commentVersion),
+  UNIQUE KEY `key_draft` (authorPHID, transactionPHID)
+
+) ENGINE=InnoDB, COLLATE utf8_general_ci;
+
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index 2284ced051..93e390d07d 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -596,7 +596,9 @@ phutil_register_library_map(array(
     'FeedPublisherHTTPWorker' => 'applications/feed/worker/FeedPublisherHTTPWorker.php',
     'FeedPublisherWorker' => 'applications/feed/worker/FeedPublisherWorker.php',
     'FeedPushWorker' => 'applications/feed/worker/FeedPushWorker.php',
-    'FilesCreateMailReceiver' => 'applications/files/mail/FilesCreateMailReceiver.php',
+    'FileCreateMailReceiver' => 'applications/files/mail/FileCreateMailReceiver.php',
+    'FileMailReceiver' => 'applications/files/mail/FileMailReceiver.php',
+    'FileReplyHandler' => 'applications/files/mail/FileReplyHandler.php',
     'HarbormasterDAO' => 'applications/harbormaster/storage/HarbormasterDAO.php',
     'HarbormasterObject' => 'applications/harbormaster/storage/HarbormasterObject.php',
     'HarbormasterRunnerWorker' => 'applications/harbormaster/worker/HarbormasterRunnerWorker.php',
@@ -1161,11 +1163,13 @@ phutil_register_library_map(array(
     'PhabricatorFeedStoryStatus' => 'applications/feed/story/PhabricatorFeedStoryStatus.php',
     'PhabricatorFeedStoryTypeConstants' => 'applications/feed/constants/PhabricatorFeedStoryTypeConstants.php',
     'PhabricatorFile' => 'applications/files/storage/PhabricatorFile.php',
+    'PhabricatorFileCommentController' => 'applications/files/controller/PhabricatorFileCommentController.php',
     'PhabricatorFileController' => 'applications/files/controller/PhabricatorFileController.php',
     'PhabricatorFileDAO' => 'applications/files/storage/PhabricatorFileDAO.php',
     'PhabricatorFileDataController' => 'applications/files/controller/PhabricatorFileDataController.php',
     'PhabricatorFileDeleteController' => 'applications/files/controller/PhabricatorFileDeleteController.php',
     'PhabricatorFileDropUploadController' => 'applications/files/controller/PhabricatorFileDropUploadController.php',
+    'PhabricatorFileEditor' => 'applications/files/editor/PhabricatorFileEditor.php',
     'PhabricatorFileImageMacro' => 'applications/macro/storage/PhabricatorFileImageMacro.php',
     'PhabricatorFileInfoController' => 'applications/files/controller/PhabricatorFileInfoController.php',
     'PhabricatorFileLinkListView' => 'view/layout/PhabricatorFileLinkListView.php',
@@ -1181,6 +1185,9 @@ phutil_register_library_map(array(
     'PhabricatorFileStorageEngineSelector' => 'applications/files/engineselector/PhabricatorFileStorageEngineSelector.php',
     'PhabricatorFileTestCase' => 'applications/files/storage/__tests__/PhabricatorFileTestCase.php',
     'PhabricatorFileTestDataGenerator' => 'applications/files/lipsum/PhabricatorFileTestDataGenerator.php',
+    'PhabricatorFileTransaction' => 'applications/files/storage/PhabricatorFileTransaction.php',
+    'PhabricatorFileTransactionComment' => 'applications/files/storage/PhabricatorFileTransactionComment.php',
+    'PhabricatorFileTransactionQuery' => 'applications/files/query/PhabricatorFileTransactionQuery.php',
     'PhabricatorFileTransformController' => 'applications/files/controller/PhabricatorFileTransformController.php',
     'PhabricatorFileUploadController' => 'applications/files/controller/PhabricatorFileUploadController.php',
     'PhabricatorFileUploadDialogController' => 'applications/files/controller/PhabricatorFileUploadDialogController.php',
@@ -2631,7 +2638,9 @@ phutil_register_library_map(array(
     'FeedPublisherHTTPWorker' => 'FeedPushWorker',
     'FeedPublisherWorker' => 'FeedPushWorker',
     'FeedPushWorker' => 'PhabricatorWorker',
-    'FilesCreateMailReceiver' => 'PhabricatorMailReceiver',
+    'FileCreateMailReceiver' => 'PhabricatorMailReceiver',
+    'FileMailReceiver' => 'PhabricatorObjectMailReceiver',
+    'FileReplyHandler' => 'PhabricatorMailReplyHandler',
     'HarbormasterDAO' => 'PhabricatorLiskDAO',
     'HarbormasterObject' => 'HarbormasterDAO',
     'HarbormasterRunnerWorker' => 'PhabricatorWorker',
@@ -3245,13 +3254,17 @@ phutil_register_library_map(array(
     'PhabricatorFile' =>
     array(
       0 => 'PhabricatorFileDAO',
-      1 => 'PhabricatorPolicyInterface',
+      1 => 'PhabricatorTokenReceiverInterface',
+      2 => 'PhabricatorSubscribableInterface',
+      3 => 'PhabricatorPolicyInterface',
     ),
+    'PhabricatorFileCommentController' => 'PhabricatorFileController',
     'PhabricatorFileController' => 'PhabricatorController',
     'PhabricatorFileDAO' => 'PhabricatorLiskDAO',
     'PhabricatorFileDataController' => 'PhabricatorFileController',
     'PhabricatorFileDeleteController' => 'PhabricatorFileController',
     'PhabricatorFileDropUploadController' => 'PhabricatorFileController',
+    'PhabricatorFileEditor' => 'PhabricatorApplicationTransactionEditor',
     'PhabricatorFileImageMacro' =>
     array(
       0 => 'PhabricatorFileDAO',
@@ -3275,6 +3288,9 @@ phutil_register_library_map(array(
     'PhabricatorFileStorageConfigurationException' => 'Exception',
     'PhabricatorFileTestCase' => 'PhabricatorTestCase',
     'PhabricatorFileTestDataGenerator' => 'PhabricatorTestDataGenerator',
+    'PhabricatorFileTransaction' => 'PhabricatorApplicationTransaction',
+    'PhabricatorFileTransactionComment' => 'PhabricatorApplicationTransactionComment',
+    'PhabricatorFileTransactionQuery' => 'PhabricatorApplicationTransactionQuery',
     'PhabricatorFileTransformController' => 'PhabricatorFileController',
     'PhabricatorFileUploadController' => 'PhabricatorFileController',
     'PhabricatorFileUploadDialogController' => 'PhabricatorFileController',
diff --git a/src/applications/files/application/PhabricatorApplicationFiles.php b/src/applications/files/application/PhabricatorApplicationFiles.php
index f8d37755a8..05590852b2 100644
--- a/src/applications/files/application/PhabricatorApplicationFiles.php
+++ b/src/applications/files/application/PhabricatorApplicationFiles.php
@@ -1,5 +1,8 @@
 <?php
 
+/**
+ * @group file
+ */
 final class PhabricatorApplicationFiles extends PhabricatorApplication {
 
   public function getBaseURI() {
@@ -48,6 +51,7 @@ final class PhabricatorApplicationFiles extends PhabricatorApplication {
         '(query/(?P<key>[^/]+)/)?' => 'PhabricatorFileListController',
         'upload/' => 'PhabricatorFileUploadController',
         'dropupload/' => 'PhabricatorFileDropUploadController',
+        'comment/(?P<id>[1-9]\d*)/' => 'PhabricatorFileCommentController',
         'delete/(?P<id>[1-9]\d*)/' => 'PhabricatorFileDeleteController',
         'info/(?P<phid>[^/]+)/' => 'PhabricatorFileInfoController',
         'data/(?P<key>[^/]+)/(?P<phid>[^/]+)/.*'
diff --git a/src/applications/files/conduit/ConduitAPI_file_Method.php b/src/applications/files/conduit/ConduitAPI_file_Method.php
index 45f525221d..0c003dd730 100644
--- a/src/applications/files/conduit/ConduitAPI_file_Method.php
+++ b/src/applications/files/conduit/ConduitAPI_file_Method.php
@@ -1,5 +1,8 @@
 <?php
 
+/**
+ * @group conduit
+ */
 abstract class ConduitAPI_file_Method extends ConduitAPIMethod {
 
   public function getApplication() {
diff --git a/src/applications/files/config/PhabricatorFilesConfigOptions.php b/src/applications/files/config/PhabricatorFilesConfigOptions.php
index 1d3b57ad14..357d8912a6 100644
--- a/src/applications/files/config/PhabricatorFilesConfigOptions.php
+++ b/src/applications/files/config/PhabricatorFilesConfigOptions.php
@@ -1,5 +1,8 @@
 <?php
 
+/**
+ * @group file
+ */
 final class PhabricatorFilesConfigOptions
   extends PhabricatorApplicationConfigOptions {
 
@@ -158,7 +161,12 @@ final class PhabricatorFilesConfigOptions
         'metamta.files.public-create-email',
         'string',
         null)
-       ->setDescription(pht('Allow uploaded files via email.')),
+        ->setDescription(pht('Allow uploaded files via email.')),
+     $this->newOption(
+        'metamta.files.subject-prefix',
+        'string',
+        '[File]')
+        ->setDescription(pht('Subject prefix for paste email.')),
      $this->newOption('files.enable-imagemagick', 'bool', false)
        ->setBoolOptions(
          array(
diff --git a/src/applications/files/controller/PhabricatorFileCommentController.php b/src/applications/files/controller/PhabricatorFileCommentController.php
new file mode 100644
index 0000000000..ab47f9fe0e
--- /dev/null
+++ b/src/applications/files/controller/PhabricatorFileCommentController.php
@@ -0,0 +1,73 @@
+<?php
+
+/**
+ * @group file
+ */
+final class PhabricatorFileCommentController
+  extends PhabricatorFileController {
+
+  private $id;
+
+  public function willProcessRequest(array $data) {
+    $this->id = idx($data, 'id');
+  }
+
+  public function processRequest() {
+    $request = $this->getRequest();
+    $user = $request->getUser();
+
+    if (!$request->isFormPost()) {
+      return new Aphront400Response();
+    }
+
+    $file = id(new PhabricatorFileQuery())
+      ->setViewer($user)
+      ->withIDs(array($this->id))
+      ->executeOne();
+    if (!$file) {
+      return new Aphront404Response();
+    }
+
+    $is_preview = $request->isPreviewRequest();
+    $draft = PhabricatorDraft::buildFromRequest($request);
+
+    $view_uri = $file->getInfoURI();
+
+    $xactions = array();
+    $xactions[] = id(new PhabricatorFileTransaction())
+      ->setTransactionType(PhabricatorTransactions::TYPE_COMMENT)
+      ->attachComment(
+        id(new PhabricatorFileTransactionComment())
+          ->setContent($request->getStr('comment')));
+
+    $editor = id(new PhabricatorFileEditor())
+      ->setActor($user)
+      ->setContinueOnNoEffect($request->isContinueRequest())
+      ->setContentSourceFromRequest($request)
+      ->setIsPreview($is_preview);
+
+    try {
+      $xactions = $editor->applyTransactions($file, $xactions);
+    } catch (PhabricatorApplicationTransactionNoEffectException $ex) {
+      return id(new PhabricatorApplicationTransactionNoEffectResponse())
+        ->setCancelURI($view_uri)
+        ->setException($ex);
+    }
+
+    if ($draft) {
+      $draft->replaceOrDelete();
+    }
+
+    if ($request->isAjax()) {
+      return id(new PhabricatorApplicationTransactionResponse())
+        ->setViewer($user)
+        ->setTransactions($xactions)
+        ->setIsPreview($is_preview)
+        ->setAnchorOffset($request->getStr('anchor'));
+    } else {
+      return id(new AphrontRedirectResponse())
+        ->setURI($view_uri);
+    }
+  }
+
+}
diff --git a/src/applications/files/controller/PhabricatorFileInfoController.php b/src/applications/files/controller/PhabricatorFileInfoController.php
index 1cb6050ffd..a7c7430982 100644
--- a/src/applications/files/controller/PhabricatorFileInfoController.php
+++ b/src/applications/files/controller/PhabricatorFileInfoController.php
@@ -21,8 +21,13 @@ final class PhabricatorFileInfoController extends PhabricatorFileController {
       return new Aphront404Response();
     }
 
-    $this->loadHandles(array($file->getAuthorPHID()));
     $phid = $file->getPHID();
+    $xactions = id(new PhabricatorFileTransactionQuery())
+      ->setViewer($user)
+      ->withObjectPHIDs(array($phid))
+      ->execute();
+
+    $this->loadHandles(array($file->getAuthorPHID()));
     $header = id(new PhabricatorHeaderView())
       ->setHeader($file->getName());
 
@@ -36,7 +41,7 @@ final class PhabricatorFileInfoController extends PhabricatorFileController {
 
     $actions = $this->buildActionView($file);
     $properties = $this->buildPropertyView($file);
-
+    $timeline = $this->buildTransactionView($file, $xactions);
     $crumbs = $this->buildApplicationCrumbs();
     $crumbs->setActionList($actions);
     $crumbs->addCrumb(
@@ -50,13 +55,64 @@ final class PhabricatorFileInfoController extends PhabricatorFileController {
         $header,
         $actions,
         $properties,
+        $timeline
       ),
       array(
         'title' => $file->getName(),
         'device'  => true,
+        'pageObjects' => array($file->getPHID()),
       ));
   }
 
+  private function buildTransactionView(
+    PhabricatorFile $file,
+    array $xactions) {
+
+    $user = $this->getRequest()->getUser();
+    $engine = id(new PhabricatorMarkupEngine())
+      ->setViewer($user);
+    foreach ($xactions as $xaction) {
+      if ($xaction->getComment()) {
+        $engine->addObject(
+          $xaction->getComment(),
+          PhabricatorApplicationTransactionComment::MARKUP_FIELD_COMMENT);
+      }
+    }
+    $engine->process();
+
+    $timeline = id(new PhabricatorApplicationTransactionView())
+      ->setUser($user)
+      ->setObjectPHID($file->getPHID())
+      ->setTransactions($xactions)
+      ->setMarkupEngine($engine);
+
+    $is_serious = PhabricatorEnv::getEnvConfig('phabricator.serious-business');
+
+    $add_comment_header = id(new PhabricatorHeaderView())
+      ->setHeader(
+        $is_serious
+          ? pht('Add Comment')
+          : pht('Question File Integrity'));
+
+    $submit_button_name = $is_serious
+      ? pht('Add Comment')
+      : pht('Debate the Bits');
+
+    $draft = PhabricatorDraft::newFromUserAndKey($user, $file->getPHID());
+
+    $add_comment_form = id(new PhabricatorApplicationTransactionCommentView())
+      ->setUser($user)
+      ->setObjectPHID($file->getPHID())
+      ->setDraft($draft)
+      ->setAction($this->getApplicationURI('/comment/'.$file->getID().'/'))
+      ->setSubmitButtonName($submit_button_name);
+
+    return array(
+      $timeline,
+      $add_comment_header,
+      $add_comment_form);
+  }
+
   private function buildActionView(PhabricatorFile $file) {
     $request = $this->getRequest();
     $user = $request->getUser();
diff --git a/src/applications/files/editor/PhabricatorFileEditor.php b/src/applications/files/editor/PhabricatorFileEditor.php
new file mode 100644
index 0000000000..d7c2709f79
--- /dev/null
+++ b/src/applications/files/editor/PhabricatorFileEditor.php
@@ -0,0 +1,89 @@
+<?php
+
+/**
+ * @group file
+ */
+final class PhabricatorFileEditor
+  extends PhabricatorApplicationTransactionEditor {
+
+  public function getTransactionTypes() {
+    $types = parent::getTransactionTypes();
+
+    $types[] = PhabricatorTransactions::TYPE_COMMENT;
+
+    return $types;
+  }
+
+  protected function getCustomTransactionOldValue(
+    PhabricatorLiskDAO $object,
+    PhabricatorApplicationTransaction $xaction) {
+
+  }
+
+  protected function getCustomTransactionNewValue(
+    PhabricatorLiskDAO $object,
+    PhabricatorApplicationTransaction $xaction) {
+
+  }
+
+  protected function applyCustomInternalTransaction(
+    PhabricatorLiskDAO $object,
+    PhabricatorApplicationTransaction $xaction) {
+  }
+
+  protected function applyCustomExternalTransaction(
+    PhabricatorLiskDAO $object,
+    PhabricatorApplicationTransaction $xaction) {
+  }
+
+  protected function supportsMail() {
+    return true;
+  }
+
+  protected function getMailSubjectPrefix() {
+    return PhabricatorEnv::getEnvConfig('metamta.files.subject-prefix');
+  }
+
+  protected function getMailTo(PhabricatorLiskDAO $object) {
+    return array(
+      $object->getAuthorPHID(),
+      $this->requireActor()->getPHID(),
+    );
+  }
+
+  protected function buildReplyHandler(PhabricatorLiskDAO $object) {
+    return id(new FileReplyHandler())
+      ->setMailReceiver($object);
+  }
+
+  protected function buildMailTemplate(PhabricatorLiskDAO $object) {
+    $id = $object->getID();
+    $name = $object->getName();
+
+    return id(new PhabricatorMetaMTAMail())
+      ->setSubject("F{$id}: {$name}")
+      ->addHeader('Thread-Topic', "F{$id}");
+  }
+
+  protected function buildMailBody(
+    PhabricatorLiskDAO $object,
+    array $xactions) {
+
+    $body = parent::buildMailBody($object, $xactions);
+
+    $body->addTextSection(
+      pht('FILE DETAIL'),
+      PhabricatorEnv::getProductionURI($object->getInfoURI()));
+
+    return $body;
+  }
+
+  protected function supportsFeed() {
+    return true;
+  }
+
+  protected function supportsSearch() {
+    return false;
+  }
+
+}
diff --git a/src/applications/files/mail/FilesCreateMailReceiver.php b/src/applications/files/mail/FileCreateMailReceiver.php
similarity index 90%
rename from src/applications/files/mail/FilesCreateMailReceiver.php
rename to src/applications/files/mail/FileCreateMailReceiver.php
index c477fb0577..fb11b7ba63 100644
--- a/src/applications/files/mail/FilesCreateMailReceiver.php
+++ b/src/applications/files/mail/FileCreateMailReceiver.php
@@ -3,7 +3,7 @@
 /**
  * @group files
  */
-final class FilesCreateMailReceiver
+final class FileCreateMailReceiver
   extends PhabricatorMailReceiver {
 
   public function isEnabled() {
@@ -48,6 +48,8 @@ final class FilesCreateMailReceiver
     } else {
       $subject = pht('You successfully uploaded a file.');
     }
+    $subject_prefix =
+      PhabricatorEnv::getEnvConfig('metamta.files.subject-prefix');
 
     $file_uris = array();
     foreach ($attachment_phids as $phid) {
@@ -61,7 +63,8 @@ final class FilesCreateMailReceiver
 
     id(new PhabricatorMetaMTAMail())
       ->addTos(array($sender->getPHID()))
-      ->setSubject('[Files] '.$subject)
+      ->setSubject($subject)
+      ->setSubjectPrefix($subject_prefix)
       ->setFrom($sender->getPHID())
       ->setRelatedPHID($first_phid)
       ->setBody($body->render())
diff --git a/src/applications/files/mail/FileMailReceiver.php b/src/applications/files/mail/FileMailReceiver.php
new file mode 100644
index 0000000000..a0ab1e9111
--- /dev/null
+++ b/src/applications/files/mail/FileMailReceiver.php
@@ -0,0 +1,40 @@
+<?php
+
+/**
+ * @group file
+ */
+final class FileMailReceiver extends PhabricatorObjectMailReceiver {
+
+  public function isEnabled() {
+    $app_class = 'PhabricatorApplicationFiles';
+    return PhabricatorApplication::isClassInstalled($app_class);
+  }
+
+  protected function getObjectPattern() {
+    return 'F[1-9]\d*';
+  }
+
+  protected function loadObject($pattern, PhabricatorUser $viewer) {
+    $id = (int)trim($pattern, 'F');
+
+    return id(new PhabricatorPasteQuery())
+      ->setViewer($viewer)
+      ->withIDs(array($id))
+      ->executeOne();
+  }
+
+  protected function processReceivedObjectMail(
+    PhabricatorMetaMTAReceivedMail $mail,
+    PhabricatorLiskDAO $object,
+    PhabricatorUser $sender) {
+
+    $handler = id(new FileReplyHandler())
+      ->setMailReceiver($object);
+
+    $handler->setActor($sender);
+    $handler->setExcludeMailRecipientPHIDs(
+      $mail->loadExcludeMailRecipientPHIDs());
+    $handler->processEmail($mail);
+  }
+
+}
diff --git a/src/applications/files/mail/FileReplyHandler.php b/src/applications/files/mail/FileReplyHandler.php
new file mode 100644
index 0000000000..2f77c815a7
--- /dev/null
+++ b/src/applications/files/mail/FileReplyHandler.php
@@ -0,0 +1,92 @@
+<?php
+
+/**
+ * @group file
+ */
+final class FileReplyHandler extends PhabricatorMailReplyHandler {
+
+  public function validateMailReceiver($mail_receiver) {
+    if (!($mail_receiver instanceof PhabricatorFile)) {
+      throw new Exception('Mail receiver is not a PhabricatorFile.');
+    }
+  }
+
+  public function getPrivateReplyHandlerEmailAddress(
+    PhabricatorObjectHandle $handle) {
+    return $this->getDefaultPrivateReplyHandlerEmailAddress($handle, 'F');
+  }
+
+  public function getPublicReplyHandlerEmailAddress() {
+    return $this->getDefaultPublicReplyHandlerEmailAddress('F');
+  }
+
+  public function getReplyHandlerInstructions() {
+    if ($this->supportsReplies()) {
+      return pht('Reply to comment or !unsubscribe.');
+    } else {
+      return null;
+    }
+  }
+
+  protected function receiveEmail(PhabricatorMetaMTAReceivedMail $mail) {
+    $actor = $this->getActor();
+    $file = $this->getMailReceiver();
+
+    $body = $mail->getCleanTextBody();
+    $body = trim($body);
+    $body = $this->enhanceBodyWithAttachments($body, $mail->getAttachments());
+
+    $content_source = PhabricatorContentSource::newForSource(
+      PhabricatorContentSource::SOURCE_EMAIL,
+      array(
+        'id' => $mail->getID(),
+      ));
+
+    $lines = explode("\n", trim($body));
+    $first_line = head($lines);
+
+    $xactions = array();
+    $command = null;
+    $matches = null;
+    if (preg_match('/^!(\w+)/', $first_line, $matches)) {
+      $lines = array_slice($lines, 1);
+      $body = implode("\n", $lines);
+      $body = trim($body);
+
+      $command = $matches[1];
+    }
+
+    switch ($command) {
+      case 'unsubscribe':
+        $xaction = id(new PhabricatorFileTransaction())
+          ->setTransactionType(PhabricatorTransactions::TYPE_SUBSCRIBERS)
+          ->setNewValue(array('-' => array($actor->getPHID())));
+        $xactions[] = $xaction;
+        break;
+    }
+
+    $xactions[] = id(new PhabricatorFileTransaction())
+      ->setTransactionType(PhabricatorTransactions::TYPE_COMMENT)
+      ->attachComment(
+       id(new PhabricatorFileTransactionComment())
+        ->setContent($body));
+
+    $editor = id(new PhabricatorFileEditor())
+      ->setActor($actor)
+      ->setContentSource($content_source)
+      ->setContinueOnNoEffect(true)
+      ->setIsPreview(false);
+
+    try {
+      $xactions = $editor->applyTransactions($file, $xactions);
+    } catch (PhabricatorApplicationTransactionNoEffectException $ex) {
+      // just do nothing, though unclear why you're sending a blank email
+      return true;
+    }
+
+    $head_xaction = head($xactions);
+    return $head_xaction->getID();
+
+  }
+
+}
diff --git a/src/applications/files/query/PhabricatorFileQuery.php b/src/applications/files/query/PhabricatorFileQuery.php
index 7ce622ead5..12b1907c34 100644
--- a/src/applications/files/query/PhabricatorFileQuery.php
+++ b/src/applications/files/query/PhabricatorFileQuery.php
@@ -1,5 +1,8 @@
 <?php
 
+/**
+ * @group file
+ */
 final class PhabricatorFileQuery
   extends PhabricatorCursorPagedPolicyAwareQuery {
 
diff --git a/src/applications/files/query/PhabricatorFileSearchEngine.php b/src/applications/files/query/PhabricatorFileSearchEngine.php
index c1129dcdf4..ed6f17e731 100644
--- a/src/applications/files/query/PhabricatorFileSearchEngine.php
+++ b/src/applications/files/query/PhabricatorFileSearchEngine.php
@@ -1,5 +1,8 @@
 <?php
 
+/**
+ * @group file
+ */
 final class PhabricatorFileSearchEngine
   extends PhabricatorApplicationSearchEngine {
 
diff --git a/src/applications/files/query/PhabricatorFileTransactionQuery.php b/src/applications/files/query/PhabricatorFileTransactionQuery.php
new file mode 100644
index 0000000000..18688b0af1
--- /dev/null
+++ b/src/applications/files/query/PhabricatorFileTransactionQuery.php
@@ -0,0 +1,13 @@
+<?php
+
+/**
+ * @group file
+ */
+final class PhabricatorFileTransactionQuery
+  extends PhabricatorApplicationTransactionQuery {
+
+  public function getTemplateApplicationTransaction() {
+    return new PhabricatorFileTransaction();
+  }
+
+}
diff --git a/src/applications/files/storage/PhabricatorFile.php b/src/applications/files/storage/PhabricatorFile.php
index ea8d951b40..d694f115a5 100644
--- a/src/applications/files/storage/PhabricatorFile.php
+++ b/src/applications/files/storage/PhabricatorFile.php
@@ -1,7 +1,13 @@
 <?php
 
+/**
+ * @group file
+ */
 final class PhabricatorFile extends PhabricatorFileDAO
-  implements PhabricatorPolicyInterface {
+  implements
+    PhabricatorTokenReceiverInterface,
+    PhabricatorSubscribableInterface,
+    PhabricatorPolicyInterface {
 
   const STORAGE_FORMAT_RAW  = 'raw';
 
@@ -16,6 +22,7 @@ final class PhabricatorFile extends PhabricatorFileDAO
   protected $secretKey;
   protected $contentHash;
   protected $metadata = array();
+  protected $mailKey;
 
   protected $storageEngine;
   protected $storageFormat;
@@ -38,6 +45,16 @@ final class PhabricatorFile extends PhabricatorFileDAO
       PhabricatorFilePHIDTypeFile::TYPECONST);
   }
 
+  public function save() {
+    if (!$this->getSecretKey()) {
+      $this->setSecretKey($this->generateSecretKey());
+    }
+    if (!$this->getMailKey()) {
+      $this->setMailKey(Filesystem::readRandomCharacters(20));
+    }
+    return parent::save();
+  }
+
   public static function readUploadedFileData($spec) {
     if (!$spec) {
       throw new Exception("No file was uploaded!");
@@ -648,13 +665,6 @@ final class PhabricatorFile extends PhabricatorFileDAO
     return ($key == $this->getSecretKey());
   }
 
-  public function save() {
-    if (!$this->getSecretKey()) {
-      $this->setSecretKey($this->generateSecretKey());
-    }
-    return parent::save();
-  }
-
   public function generateSecretKey() {
     return Filesystem::readRandomCharacters(20);
   }
@@ -820,4 +830,23 @@ final class PhabricatorFile extends PhabricatorFileDAO
     return false;
   }
 
+
+/* -(  PhabricatorSubscribableInterface Implementation  )-------------------- */
+
+
+  public function isAutomaticallySubscribed($phid) {
+    return ($this->authorPHID == $phid);
+  }
+
+
+/* -(  PhabricatorTokenReceiverInterface  )---------------------------------- */
+
+
+  public function getUsersToNotifyOfTokenGiven() {
+    return array(
+      $this->getAuthorPHID(),
+    );
+  }
+
+
 }
diff --git a/src/applications/files/storage/PhabricatorFileDAO.php b/src/applications/files/storage/PhabricatorFileDAO.php
index e8a49b7a46..b8999a7122 100644
--- a/src/applications/files/storage/PhabricatorFileDAO.php
+++ b/src/applications/files/storage/PhabricatorFileDAO.php
@@ -1,5 +1,8 @@
 <?php
 
+/**
+ * @group file
+ */
 abstract class PhabricatorFileDAO extends PhabricatorLiskDAO {
 
   public function getApplicationName() {
diff --git a/src/applications/files/storage/PhabricatorFileStorageBlob.php b/src/applications/files/storage/PhabricatorFileStorageBlob.php
index 7182eb1ea7..38a7e46695 100644
--- a/src/applications/files/storage/PhabricatorFileStorageBlob.php
+++ b/src/applications/files/storage/PhabricatorFileStorageBlob.php
@@ -3,7 +3,7 @@
 /**
  * Simple blob store DAO for @{class:PhabricatorMySQLFileStorageEngine}.
  *
- * @group filestorage
+ * @group file
  */
 final class PhabricatorFileStorageBlob extends PhabricatorFileDAO {
   // max_allowed_packet defaults to 1 MiB, escaping can make the data twice
diff --git a/src/applications/files/storage/PhabricatorFileTransaction.php b/src/applications/files/storage/PhabricatorFileTransaction.php
new file mode 100644
index 0000000000..02a2f1670b
--- /dev/null
+++ b/src/applications/files/storage/PhabricatorFileTransaction.php
@@ -0,0 +1,21 @@
+<?php
+
+/**
+ * @group file
+ */
+final class PhabricatorFileTransaction
+  extends PhabricatorApplicationTransaction {
+
+  public function getApplicationName() {
+    return 'file';
+  }
+
+  public function getApplicationTransactionType() {
+    return PhabricatorFilePHIDTypeFile::TYPECONST;
+  }
+
+  public function getApplicationTransactionCommentObject() {
+    return new PhabricatorFileTransactionComment();
+  }
+
+}
diff --git a/src/applications/files/storage/PhabricatorFileTransactionComment.php b/src/applications/files/storage/PhabricatorFileTransactionComment.php
new file mode 100644
index 0000000000..9323d49159
--- /dev/null
+++ b/src/applications/files/storage/PhabricatorFileTransactionComment.php
@@ -0,0 +1,17 @@
+<?php
+
+/**
+ * @group file
+ */
+final class PhabricatorFileTransactionComment
+  extends PhabricatorApplicationTransactionComment {
+
+  public function getApplicationTransactionObject() {
+    return new PhabricatorFileTransaction();
+  }
+
+  public function shouldUseMarkupCache($field) {
+    // Only cache submitted comments.
+    return ($this->getTransactionPHID() != null);
+  }
+}
diff --git a/src/applications/files/storage/PhabricatorTransformedFile.php b/src/applications/files/storage/PhabricatorTransformedFile.php
index e77f1ddffb..cc28210efa 100644
--- a/src/applications/files/storage/PhabricatorTransformedFile.php
+++ b/src/applications/files/storage/PhabricatorTransformedFile.php
@@ -1,5 +1,8 @@
 <?php
 
+/**
+ * @group file
+ */
 final class PhabricatorTransformedFile extends PhabricatorFileDAO {
 
   protected $originalPHID;
diff --git a/src/applications/files/storage/__tests__/PhabricatorFileTestCase.php b/src/applications/files/storage/__tests__/PhabricatorFileTestCase.php
index ff0068bacd..b9922ac2cb 100644
--- a/src/applications/files/storage/__tests__/PhabricatorFileTestCase.php
+++ b/src/applications/files/storage/__tests__/PhabricatorFileTestCase.php
@@ -1,5 +1,8 @@
 <?php
 
+/**
+ * @group file
+ */
 final class PhabricatorFileTestCase extends PhabricatorTestCase {
 
   public function getPhabricatorTestCaseConfiguration() {
diff --git a/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php b/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php
index 7fcd71c1cf..9d81e7daf2 100644
--- a/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php
+++ b/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php
@@ -1559,6 +1559,19 @@ final class PhabricatorBuiltinPatchList extends PhabricatorSQLPatchList {
         'type' => 'sql',
         'name' => $this->getPatchPath('20130826.divinernode.sql'),
       ),
+      '20130820.filexactions.sql' => array(
+        'type' => 'sql',
+        'name' => $this->getPatchPath('20130820.filexactions.sql'),
+      ),
+      '20130820.filemailkey.sql' => array(
+        'type' => 'sql',
+        'name' => $this->getPatchPath('20130820.filemailkey.sql'),
+      ),
+      '20130820.file-mailkey-populate.php' => array(
+        'type' => 'php',
+        'name' =>
+          $this->getPatchPath('20130820.file-mailkey-populate.php'),
+      ),
     );
   }
 }