diff --git a/resources/sql/patches/20130728.ponderunique.php b/resources/sql/patches/20130728.ponderunique.php
new file mode 100644
index 0000000000..94a45ae786
--- /dev/null
+++ b/resources/sql/patches/20130728.ponderunique.php
@@ -0,0 +1,58 @@
+<?php
+
+$map = array();
+
+echo "Merging duplicate answers by authors...\n";
+
+$atable = new PonderAnswer();
+$conn_w = $atable->establishConnection('w');
+$conn_w->openTransaction();
+
+$answers = new LiskMigrationIterator(new PonderAnswer());
+foreach ($answers as $answer) {
+  $aid = $answer->getID();
+  $qid = $answer->getQuestionID();
+  $author_phid = $answer->getAuthorPHID();
+
+  echo "Processing answer ID #{$aid}...\n";
+
+  if (empty($map[$qid][$author_phid])) {
+    echo "Answer is unique.\n";
+    $map[$qid][$author_phid] = $answer;
+    continue;
+  } else {
+    echo "Merging answer.\n";
+    $target = $map[$qid][$author_phid];
+    queryfx(
+      $conn_w,
+      'UPDATE %T SET content = %s WHERE id = %d',
+      $target->getTableName(),
+
+      $target->getContent().
+      "\n\n".
+      "---".
+      "\n\n".
+      "> (This content was automatically merged from another answer by the ".
+      "same author.)".
+      "\n\n".
+      $answer->getContent(),
+
+      $target->getID());
+
+    queryfx(
+      $conn_w,
+      'DELETE FROM %T WHERE id = %d',
+      $target->getTableName(),
+      $answer->getID());
+
+    queryfx(
+      $conn_w,
+      'UPDATE %T SET targetPHID = %s WHERE targetPHID = %s',
+      'ponder_comment',
+      $target->getPHID(),
+      $answer->getPHID());
+  }
+}
+
+$conn_w->saveTransaction();
+echo "Done.\n";
diff --git a/resources/sql/patches/20130728.ponderuniquekey.sql b/resources/sql/patches/20130728.ponderuniquekey.sql
new file mode 100644
index 0000000000..721be2ff6d
--- /dev/null
+++ b/resources/sql/patches/20130728.ponderuniquekey.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_ponder.ponder_answer
+  ADD UNIQUE KEY `key_oneanswerperquestion` (questionID, authorPHID);
diff --git a/src/applications/ponder/controller/PonderQuestionViewController.php b/src/applications/ponder/controller/PonderQuestionViewController.php
index 1368da6b7d..9f8536c8a0 100644
--- a/src/applications/ponder/controller/PonderQuestionViewController.php
+++ b/src/applications/ponder/controller/PonderQuestionViewController.php
@@ -27,11 +27,18 @@ final class PonderQuestionViewController extends PonderController {
     $question_xactions = $this->buildQuestionTransactions($question);
     $answers = $this->buildAnswers($question->getAnswers());
 
-    $answer_add_panel = new PonderAddAnswerView();
-    $answer_add_panel
-      ->setQuestion($question)
-      ->setUser($user)
-      ->setActionURI("/ponder/answer/add/");
+    $authors = mpull($question->getAnswers(), null, 'getAuthorPHID');
+    if (isset($authors[$user->getPHID()])) {
+      // TODO: Make this pretty
+      $answer_add_panel = pht(
+        'You have already answered this question.');
+    } else {
+      $answer_add_panel = new PonderAddAnswerView();
+      $answer_add_panel
+        ->setQuestion($question)
+        ->setUser($user)
+        ->setActionURI("/ponder/answer/add/");
+    }
 
     $header = id(new PhabricatorHeaderView())
       ->setHeader($question->getTitle());
@@ -268,10 +275,15 @@ final class PonderQuestionViewController extends PonderController {
     $view->invokeWillRenderEvent();
 
     $view->addTextContent(
-      PhabricatorMarkupEngine::renderOneObject(
-        $answer,
-        $answer->getMarkupField(),
-        $viewer));
+      phutil_tag(
+        'div',
+        array(
+          'class' => 'phabricator-remarkup',
+        ),
+        PhabricatorMarkupEngine::renderOneObject(
+          $answer,
+          $answer->getMarkupField(),
+          $viewer)));
 
     return $view;
   }
diff --git a/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php b/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php
index db34c66d02..31c0bc49f6 100644
--- a/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php
+++ b/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php
@@ -1487,6 +1487,14 @@ final class PhabricatorBuiltinPatchList extends PhabricatorSQLPatchList {
         'type' => 'sql',
         'name' => $this->getPatchPath('20130726.ponderxactions.sql'),
       ),
+      '20130728.ponderunique.php' => array(
+        'type' => 'php',
+        'name' => $this->getPatchPath('20130728.ponderunique.php'),
+      ),
+      '20130728.ponderuniquekey.sql' => array(
+        'type' => 'sql',
+        'name' => $this->getPatchPath('20130728.ponderuniquekey.sql'),
+      ),
     );
   }
 }