diff --git a/framework/core/js/forum/src/components/join-activity.js b/framework/core/js/forum/src/components/joined-activity.js
similarity index 88%
rename from framework/core/js/forum/src/components/join-activity.js
rename to framework/core/js/forum/src/components/joined-activity.js
index bce3ee5bf..d5bef94cf 100644
--- a/framework/core/js/forum/src/components/join-activity.js
+++ b/framework/core/js/forum/src/components/joined-activity.js
@@ -2,7 +2,7 @@ import Component from 'flarum/component';
 import humanTime from 'flarum/helpers/human-time';
 import avatar from 'flarum/helpers/avatar';
 
-export default class JoinActivity extends Component {
+export default class JoinedActivity extends Component {
   view() {
     var activity = this.props.activity;
     var user = activity.user();
diff --git a/framework/core/js/forum/src/components/post-activity.js b/framework/core/js/forum/src/components/posted-activity.js
similarity index 80%
rename from framework/core/js/forum/src/components/post-activity.js
rename to framework/core/js/forum/src/components/posted-activity.js
index 8cbf66263..9b62d620a 100644
--- a/framework/core/js/forum/src/components/post-activity.js
+++ b/framework/core/js/forum/src/components/posted-activity.js
@@ -4,11 +4,11 @@ import avatar from 'flarum/helpers/avatar';
 import listItems from 'flarum/helpers/list-items';
 import ItemList from 'flarum/utils/item-list';
 
-export default class PostActivity extends Component {
+export default class PostedActivity extends Component {
   view() {
     var activity = this.props.activity;
     var user = activity.user();
-    var post = activity.post();
+    var post = activity.subject();
     var discussion = post.discussion();
 
     return m('div', [
@@ -23,7 +23,7 @@ export default class PostActivity extends Component {
         near: post.number()
       }), config: m.route}, [
         m('ul.list-inline', listItems(this.headerItems().toArray())),
-        m('div.body', m.trust(post.contentHtml()))
+        m('div.body', m.trust(post.excerpt()))
       ])
     ]);
   }
@@ -31,7 +31,7 @@ export default class PostActivity extends Component {
   headerItems() {
     var items = new ItemList();
 
-    items.add('title', m('h3.title', this.props.activity.post().discussion().title()));
+    items.add('title', m('h3.title', this.props.activity.subject().discussion().title()));
 
     return items;
   }
diff --git a/framework/core/js/forum/src/initializers/components.js b/framework/core/js/forum/src/initializers/components.js
index 92cb63ab8..f71a69909 100644
--- a/framework/core/js/forum/src/initializers/components.js
+++ b/framework/core/js/forum/src/initializers/components.js
@@ -1,21 +1,22 @@
 import CommentPost from 'flarum/components/comment-post';
 import DiscussionRenamedPost from 'flarum/components/discussion-renamed-post';
-import PostActivity from 'flarum/components/post-activity';
-import JoinActivity from 'flarum/components/join-activity';
+import PostedActivity from 'flarum/components/posted-activity';
+import JoinedActivity from 'flarum/components/joined-activity';
 import DiscussionRenamedNotification from 'flarum/components/discussion-renamed-notification';
 
 export default function(app) {
   app.postComponentRegistry = {
-    comment: CommentPost,
-    discussionRenamed: DiscussionRenamedPost
+    'comment': CommentPost,
+    'discussionRenamed': DiscussionRenamedPost
   };
 
   app.activityComponentRegistry = {
-    post: PostActivity,
-    join: JoinActivity
+    'posted': PostedActivity,
+    'startedDiscussion': PostedActivity,
+    'joined': JoinedActivity
   };
 
   app.notificationComponentRegistry = {
-    discussionRenamed: DiscussionRenamedNotification
+    'discussionRenamed': DiscussionRenamedNotification
   };
 }
diff --git a/framework/core/js/forum/src/initializers/routes.js b/framework/core/js/forum/src/initializers/routes.js
index 97c8aa031..0ad18b168 100644
--- a/framework/core/js/forum/src/initializers/routes.js
+++ b/framework/core/js/forum/src/initializers/routes.js
@@ -13,8 +13,8 @@ export default function(app) {
 
     'user':             ['/u/:username', ActivityPage.component()],
     'user.activity':    ['/u/:username', ActivityPage.component()],
-    'user.discussions': ['/u/:username/discussions', ActivityPage.component({filter: 'discussion'})],
-    'user.posts':       ['/u/:username/posts', ActivityPage.component({filter: 'post'})],
+    'user.discussions': ['/u/:username/discussions', ActivityPage.component({filter: 'startedDiscussion'})],
+    'user.posts':       ['/u/:username/posts', ActivityPage.component({filter: 'posted'})],
 
     'settings':         ['/settings', SettingsPage.component()]
   };
diff --git a/framework/core/js/lib/models/activity.js b/framework/core/js/lib/models/activity.js
index 0d620b3bb..e2ddab39b 100644
--- a/framework/core/js/lib/models/activity.js
+++ b/framework/core/js/lib/models/activity.js
@@ -8,7 +8,6 @@ Activity.prototype.content = Model.prop('content');
 Activity.prototype.time = Model.prop('time', Model.date);
 
 Activity.prototype.user = Model.one('user');
-Activity.prototype.sender = Model.one('sender');
-Activity.prototype.post = Model.one('post');
+Activity.prototype.subject = Model.one('subject');
 
 export default Activity;
diff --git a/framework/core/migrations/2015_02_24_000000_create_activity_table.php b/framework/core/migrations/2015_02_24_000000_create_activity_table.php
index 6b5e96a6d..a0a601641 100644
--- a/framework/core/migrations/2015_02_24_000000_create_activity_table.php
+++ b/framework/core/migrations/2015_02_24_000000_create_activity_table.php
@@ -14,11 +14,10 @@ class CreateActivityTable extends Migration
     public function up()
     {
         Schema::create('activity', function (Blueprint $table) {
-        
             $table->increments('id');
             $table->integer('user_id')->unsigned();
-            $table->integer('sender_id')->unsigned()->nullable();
             $table->string('type', 100);
+            $table->integer('subject_id')->unsigned()->nullable();
             $table->binary('data')->nullable();
             $table->dateTime('time');
         });
diff --git a/framework/core/src/Api/Actions/Activity/IndexAction.php b/framework/core/src/Api/Actions/Activity/IndexAction.php
index 42c89331a..dc9a42a70 100644
--- a/framework/core/src/Api/Actions/Activity/IndexAction.php
+++ b/framework/core/src/Api/Actions/Activity/IndexAction.php
@@ -32,12 +32,9 @@ class IndexAction extends SerializeCollectionAction
      * @var array
      */
     public static $include = [
-        'sender' => true,
-        'post' => true,
-        'post.user' => true,
-        'post.discussion' => true,
-        'post.discussion.startUser' => true,
-        'post.discussion.lastUser' => true
+        'subject' => true,
+        'subject.user' => true,
+        'subject.discussion' => true
     ];
 
     /**
@@ -73,6 +70,7 @@ class IndexAction extends SerializeCollectionAction
 
         $user = $this->users->findOrFail($request->get('users'), $actor);
 
-        return $this->activity->findByUser($user->id, $actor, $request->limit, $request->offset, $request->get('type'));
+        return $this->activity->findByUser($user->id, $actor, $request->limit, $request->offset, $request->get('type'))
+            ->load($request->include);
     }
 }
diff --git a/framework/core/src/Api/Serializers/ActivitySerializer.php b/framework/core/src/Api/Serializers/ActivitySerializer.php
index 2348598e4..4dd10b8c9 100644
--- a/framework/core/src/Api/Serializers/ActivitySerializer.php
+++ b/framework/core/src/Api/Serializers/ActivitySerializer.php
@@ -9,6 +9,17 @@ class ActivitySerializer extends BaseSerializer
      */
     protected $type = 'activity';
 
+    /**
+     * A map of activity types (key) to the serializer that should be used to
+     * output the activity's subject (value).
+     *
+     * @var array
+     */
+    public static $subjects = [
+        'posted' => 'Flarum\Api\Serializers\PostBasicSerializer',
+        'joined' => 'Flarum\Api\Serializers\UserBasicSerializer'
+    ];
+
     /**
      * Serialize attributes of an Activity model for JSON output.
      *
@@ -18,9 +29,7 @@ class ActivitySerializer extends BaseSerializer
     protected function attributes($activity)
     {
         $attributes = [
-            'id'   => ((int) $activity->id) ?: str_random(5),
             'contentType' => $activity->type,
-            'content' => json_encode($activity->data),
             'time' => $activity->time->toRFC3339String()
         ];
 
@@ -37,8 +46,10 @@ class ActivitySerializer extends BaseSerializer
         return $this->hasOne('Flarum\Api\Serializers\UserBasicSerializer');
     }
 
-    public function post()
+    public function subject()
     {
-        return $this->hasOne('Flarum\Api\Serializers\PostSerializer');
+        return $this->hasOne(function ($activity) {
+            return static::$subjects[$activity->type];
+        });
     }
 }
diff --git a/framework/core/src/Core/Activity/ActivityAbstract.php b/framework/core/src/Core/Activity/ActivityAbstract.php
new file mode 100644
index 000000000..d39e67b42
--- /dev/null
+++ b/framework/core/src/Core/Activity/ActivityAbstract.php
@@ -0,0 +1,5 @@
+<?php namespace Flarum\Core\Activity;
+
+abstract class ActivityAbstract implements ActivityInterface
+{
+}
diff --git a/framework/core/src/Core/Activity/ActivityInterface.php b/framework/core/src/Core/Activity/ActivityInterface.php
new file mode 100644
index 000000000..c4bf9a648
--- /dev/null
+++ b/framework/core/src/Core/Activity/ActivityInterface.php
@@ -0,0 +1,32 @@
+<?php namespace Flarum\Core\Activity;
+
+interface ActivityInterface
+{
+    /**
+     * Get the model that is the subject of this activity.
+     *
+     * @return \Flarum\Core\Models\Model
+     */
+    public function getSubject();
+
+    /**
+     * Get the time at which the activity occurred.
+     *
+     * @return mixed
+     */
+    public function getTime();
+
+    /**
+     * Get the serialized type of this activity.
+     *
+     * @return string
+     */
+    public static function getType();
+
+    /**
+     * Get the name of the model class for the subject of this activity.
+     *
+     * @return string
+     */
+    public static function getSubjectModel();
+}
diff --git a/framework/core/src/Core/Activity/ActivitySyncer.php b/framework/core/src/Core/Activity/ActivitySyncer.php
new file mode 100644
index 000000000..04171d5cf
--- /dev/null
+++ b/framework/core/src/Core/Activity/ActivitySyncer.php
@@ -0,0 +1,53 @@
+<?php namespace Flarum\Core\Activity;
+
+use Flarum\Core\Repositories\ActivityRepositoryInterface;
+use Flarum\Core\Models\Activity;
+
+class ActivitySyncer
+{
+    protected $activity;
+
+    public function __construct(ActivityRepositoryInterface $activity)
+    {
+        $this->activity = $activity;
+    }
+
+    /**
+     * Sync a piece of activity so that it is present for the specified users,
+     * and not present for anyone else.
+     *
+     * @param \Flarum\Core\Activity\ActivityInterface $activity
+     * @param \Flarum\Core\Models\User[] $users
+     * @return void
+     */
+    public function sync(ActivityInterface $activity, array $users)
+    {
+        Activity::unguard();
+
+        $attributes = [
+            'type'       => $activity::getType(),
+            'subject_id' => $activity->getSubject()->id,
+            'time'       => $activity->getTime()
+        ];
+
+        $toDelete = Activity::where($attributes)->get();
+        $toInsert = [];
+
+        foreach ($users as $user) {
+            $existing = $toDelete->where('user_id', $user->id)->first();
+
+            if ($k = $toDelete->search($existing)) {
+                $toDelete->pull($k);
+            } else {
+                $toInsert[] = $attributes + ['user_id' => $user->id];
+            }
+        }
+
+        if (count($toDelete)) {
+            Activity::whereIn('id', $toDelete->lists('id'))->delete();
+        }
+        if (count($toInsert)) {
+            Activity::insert($toInsert);
+        }
+    }
+}
diff --git a/framework/core/src/Core/Activity/JoinedActivity.php b/framework/core/src/Core/Activity/JoinedActivity.php
new file mode 100644
index 000000000..38b6bf4ce
--- /dev/null
+++ b/framework/core/src/Core/Activity/JoinedActivity.php
@@ -0,0 +1,33 @@
+<?php namespace Flarum\Core\Activity;
+
+use Flarum\Core\Models\User;
+
+class JoinedActivity extends ActivityAbstract
+{
+    protected $user;
+
+    public function __construct(User $user)
+    {
+        $this->user = $user;
+    }
+
+    public function getSubject()
+    {
+        return $this->user;
+    }
+
+    public function getTime()
+    {
+        return $this->user->join_time;
+    }
+
+    public static function getType()
+    {
+        return 'joined';
+    }
+
+    public static function getSubjectModel()
+    {
+        return 'Flarum\Core\Models\User';
+    }
+}
diff --git a/framework/core/src/Core/Activity/PostedActivity.php b/framework/core/src/Core/Activity/PostedActivity.php
new file mode 100644
index 000000000..8c306c663
--- /dev/null
+++ b/framework/core/src/Core/Activity/PostedActivity.php
@@ -0,0 +1,33 @@
+<?php namespace Flarum\Core\Activity;
+
+use Flarum\Core\Models\Post;
+
+class PostedActivity extends ActivityAbstract
+{
+    protected $post;
+
+    public function __construct(Post $post)
+    {
+        $this->post = $post;
+    }
+
+    public function getSubject()
+    {
+        return $this->post;
+    }
+
+    public function getTime()
+    {
+        return $this->post->time;
+    }
+
+    public static function getType()
+    {
+        return 'posted';
+    }
+
+    public static function getSubjectModel()
+    {
+        return 'Flarum\Core\Models\Post';
+    }
+}
diff --git a/framework/core/src/Core/Activity/StartedDiscussionActivity.php b/framework/core/src/Core/Activity/StartedDiscussionActivity.php
new file mode 100644
index 000000000..9b7b3a550
--- /dev/null
+++ b/framework/core/src/Core/Activity/StartedDiscussionActivity.php
@@ -0,0 +1,9 @@
+<?php namespace Flarum\Core\Activity;
+
+class StartedDiscussionActivity extends PostedActivity
+{
+    public static function getType()
+    {
+        return 'startedDiscussion';
+    }
+}
diff --git a/framework/core/src/Core/CoreServiceProvider.php b/framework/core/src/Core/CoreServiceProvider.php
index 32d792960..3c7ff5a7b 100644
--- a/framework/core/src/Core/CoreServiceProvider.php
+++ b/framework/core/src/Core/CoreServiceProvider.php
@@ -16,6 +16,7 @@ use League\Flysystem\Adapter\Local;
 use Flarum\Core\Events\RegisterDiscussionGambits;
 use Flarum\Core\Events\RegisterUserGambits;
 use Flarum\Extend\Permission;
+use Flarum\Extend\ActivityType;
 use Flarum\Extend\NotificationType;
 
 class CoreServiceProvider extends ServiceProvider
@@ -46,9 +47,16 @@ class CoreServiceProvider extends ServiceProvider
         });
 
         $events->subscribe('Flarum\Core\Handlers\Events\DiscussionRenamedNotifier');
+        $events->subscribe('Flarum\Core\Handlers\Events\UserActivitySyncer');
+
         $this->extend(
             (new NotificationType('Flarum\Core\Notifications\DiscussionRenamedNotification', 'Flarum\Api\Serializers\DiscussionBasicSerializer'))
                 ->enableByDefault('alert'),
+
+            (new ActivityType('Flarum\Core\Activity\PostedActivity', 'Flarum\Api\Serializers\PostBasicSerializer')),
+            (new ActivityType('Flarum\Core\Activity\StartedDiscussionActivity', 'Flarum\Api\Serializers\PostBasicSerializer')),
+
+            (new ActivityType('Flarum\Core\Activity\JoinedActivity', 'Flarum\Api\Serializers\UserBasicSerializer'))
         );
     }
 
diff --git a/framework/core/src/Core/Handlers/Events/UserActivitySyncer.php b/framework/core/src/Core/Handlers/Events/UserActivitySyncer.php
new file mode 100755
index 000000000..369222b90
--- /dev/null
+++ b/framework/core/src/Core/Handlers/Events/UserActivitySyncer.php
@@ -0,0 +1,76 @@
+<?php namespace Flarum\Core\Handlers\Events;
+
+use Flarum\Core\Activity\ActivitySyncer;
+use Flarum\Core\Activity\PostedActivity;
+use Flarum\Core\Activity\StartedDiscussionActivity;
+use Flarum\Core\Activity\JoinedActivity;
+use Flarum\Core\Events\PostWasPosted;
+use Flarum\Core\Events\PostWasDeleted;
+use Flarum\Core\Events\PostWasHidden;
+use Flarum\Core\Events\PostWasRestored;
+use Flarum\Core\Events\UserWasRegistered;
+use Flarum\Core\Models\Post;
+use Illuminate\Contracts\Events\Dispatcher;
+
+class UserActivitySyncer
+{
+    protected $activity;
+
+    public function __construct(ActivitySyncer $activity)
+    {
+        $this->activity = $activity;
+    }
+
+    public function subscribe(Dispatcher $events)
+    {
+        $events->listen('Flarum\Core\Events\PostWasPosted', __CLASS__.'@whenPostWasPosted');
+        $events->listen('Flarum\Core\Events\PostWasHidden', __CLASS__.'@whenPostWasHidden');
+        $events->listen('Flarum\Core\Events\PostWasRestored', __CLASS__.'@whenPostWasRestored');
+        $events->listen('Flarum\Core\Events\PostWasDeleted', __CLASS__.'@whenPostWasDeleted');
+        $events->listen('Flarum\Core\Events\UserWasRegistered', __CLASS__.'@whenUserWasRegistered');
+    }
+
+    public function whenPostWasPosted(PostWasPosted $event)
+    {
+        $this->postBecameVisible($event->post);
+    }
+
+    public function whenPostWasHidden(PostWasHidden $event)
+    {
+        $this->postBecameInvisible($event->post);
+    }
+
+    public function whenPostWasRestored(PostWasRestored $event)
+    {
+        $this->postBecameVisible($event->post);
+    }
+
+    public function whenPostWasDeleted(PostWasDeleted $event)
+    {
+        $this->postBecameInvisible($event->post);
+    }
+
+    public function whenUserWasRegistered(UserWasRegistered $event)
+    {
+        $this->activity->sync(new JoinedActivity($event->user), [$event->user]);
+    }
+
+    protected function postBecameVisible(Post $post)
+    {
+        $activity = $this->postedActivity($post);
+
+        $this->activity->sync($activity, [$post->user]);
+    }
+
+    protected function postBecameInvisible(Post $post)
+    {
+        $activity = $this->postedActivity($post);
+
+        $this->activity->sync($activity, []);
+    }
+
+    protected function postedActivity(Post $post)
+    {
+        return $post->number === 1 ? new StartedDiscussionActivity($post) : new PostedActivity($post);
+    }
+}
diff --git a/framework/core/src/Core/Models/Activity.php b/framework/core/src/Core/Models/Activity.php
index e75860b71..d12c6434e 100644
--- a/framework/core/src/Core/Models/Activity.php
+++ b/framework/core/src/Core/Models/Activity.php
@@ -16,6 +16,13 @@ class Activity extends Model
      */
     protected $dates = ['time'];
 
+    /**
+     *
+     *
+     * @var array
+     */
+    protected static $subjects = [];
+
     /**
      * Unserialize the data attribute.
      *
@@ -47,23 +54,27 @@ class Activity extends Model
         return $this->belongsTo('Flarum\Core\Models\User', 'user_id');
     }
 
-    /**
-     * Define the relationship with the activity's sender.
-     *
-     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
-     */
-    public function sender()
+    public function subject()
     {
-        return $this->belongsTo('Flarum\Core\Models\User', 'sender_id');
+        return $this->mappedMorphTo(static::$subjects, 'subject', 'type', 'subject_id');
+    }
+
+    public static function getTypes()
+    {
+        return static::$subjects;
     }
 
     /**
-     * Define the relationship with the activity's sender.
+     * Register a notification type.
      *
-     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
+     * @param  string $type
+     * @param  string $class
+     * @return void
      */
-    public function post()
+    public static function registerType($class)
     {
-        return $this->belongsTo('Flarum\Core\Models\Post', 'post_id');
+        if ($subject = $class::getSubjectModel()) {
+            static::$subjects[$class::getType()] = $subject;
+        }
     }
 }
diff --git a/framework/core/src/Core/Notifications/Types/AlertableNotification.php b/framework/core/src/Core/Notifications/Types/AlertableNotification.php
deleted file mode 100644
index 25130c430..000000000
--- a/framework/core/src/Core/Notifications/Types/AlertableNotification.php
+++ /dev/null
@@ -1,32 +0,0 @@
-<?php namespace Flarum\Core\Notifications\Types;
-
-interface AlertableNotification
-{
-    /**
-     * Get the data to be stored in the alert.
-     *
-     * @return array
-     */
-    public function getAlertData();
-
-    /**
-     * Get the user that sent the notification.
-     *
-     * @return \Flarum\Core\Models\User|null
-     */
-    public function getSender();
-
-    /**
-     * Get the model that the notification is about.
-     *
-     * @return \Flarum\Core\Models\Model
-     */
-    public function getSubject();
-
-    /**
-     * Get the class name of this notification type's subject model.
-     *
-     * @return string
-     */
-    public static function getSubjectModel();
-}
diff --git a/framework/core/src/Core/Repositories/EloquentActivityRepository.php b/framework/core/src/Core/Repositories/EloquentActivityRepository.php
index e027c93d2..809be04bc 100644
--- a/framework/core/src/Core/Repositories/EloquentActivityRepository.php
+++ b/framework/core/src/Core/Repositories/EloquentActivityRepository.php
@@ -1,39 +1,22 @@
 <?php namespace Flarum\Core\Repositories;
 
 use Flarum\Core\Models\Activity;
-use Flarum\Core\Models\Post;
 use Flarum\Core\Models\User;
 
 class EloquentActivityRepository implements ActivityRepositoryInterface
 {
-    public function findByUser($userId, User $viewer, $count = null, $start = 0, $type = null)
+    public function findByUser($userId, User $viewer, $limit = null, $offset = 0, $type = null)
     {
-        // This is all very rough and needs to be cleaned up
+        $query = Activity::where('user_id', $userId)
+            ->whereIn('type', array_keys(Activity::getTypes()))
+            ->orderBy('time', 'desc')
+            ->skip($offset)
+            ->take($limit);
 
-        $null = \DB::raw('NULL');
-        $query = Activity::with('sender')->select('id', 'user_id', 'sender_id', 'type', 'data', 'time', \DB::raw('NULL as post_id'))->where('user_id', $userId);
-
-        if ($type) {
+        if ($type !== null) {
             $query->where('type', $type);
         }
 
-        $posts = Post::whereCan($viewer, 'view')->with('post', 'post.discussion', 'post.user', 'post.discussion.startUser', 'post.discussion.lastUser')->select(\DB::raw("CONCAT('post', id)"), 'user_id', $null, \DB::raw("'post'"), $null, 'time', 'id')->where('user_id', $userId)->where('type', 'comment')->whereNull('hide_time');
-
-        if ($type === 'post') {
-            $posts->where('number', '>', 1);
-        } elseif ($type === 'discussion') {
-            $posts->where('number', 1);
-        }
-
-        if (!$type) {
-            $join = User::select(\DB::raw("CONCAT('join', id)"), 'id', 'id', \DB::raw("'join'"), $null, 'join_time', $null)->where('id', $userId);
-            $query->union($join->getQuery());
-        }
-
-        return $query->union($posts->getQuery())
-            ->orderBy('time', 'desc')
-            ->skip($start)
-            ->take($count)
-            ->get();
+        return $query->get();
     }
 }
diff --git a/framework/core/src/Extend/ActivityType.php b/framework/core/src/Extend/ActivityType.php
new file mode 100644
index 000000000..92a86c079
--- /dev/null
+++ b/framework/core/src/Extend/ActivityType.php
@@ -0,0 +1,27 @@
+<?php namespace Flarum\Extend;
+
+use Illuminate\Foundation\Application;
+use Flarum\Core\Models\Activity;
+use Flarum\Api\Serializers\ActivitySerializer;
+
+class ActivityType implements ExtenderInterface
+{
+    protected $class;
+
+    protected $serializer;
+
+    public function __construct($class, $serializer)
+    {
+        $this->class = $class;
+        $this->serializer = $serializer;
+    }
+
+    public function extend(Application $app)
+    {
+        $class = $this->class;
+
+        Activity::registerType($class);
+
+        ActivitySerializer::$subjects[$class::getType()] = $this->serializer;
+    }
+}