diff --git a/app/Models/Changeset.php b/app/Models/Changeset.php
index 26d9335..770256f 100644
--- a/app/Models/Changeset.php
+++ b/app/Models/Changeset.php
@@ -4,6 +4,9 @@ namespace App\Models;
 
 use Illuminate\Database\Eloquent\Model;
 
+/**
+ * A patch describing changes to apply or applied to a data table.
+ */
 class Changeset extends Model
 {
     /** Parent data table */
@@ -17,4 +20,32 @@ class Changeset extends Model
     {
         return $this->belongsTo(User::class, 'author_id');
     }
+
+    /** Reports of this changeset */
+    public function reportsOf()
+    {
+        return $this->morphMany(ContentReport::class, 'object');
+    }
+
+    /**
+     * Scope for pending changesets
+     *
+     * @param \Illuminate\Database\Eloquent\Builder $query
+     * @return \Illuminate\Database\Eloquent\Builder
+     */
+    public function scopePending($query)
+    {
+        return $query->where('applied', false);
+    }
+
+    /**
+     * Scope for applied changesets
+     *
+     * @param \Illuminate\Database\Eloquent\Builder $query
+     * @return \Illuminate\Database\Eloquent\Builder
+     */
+    public function scopeApplied($query)
+    {
+        return $query->where('applied', true);
+    }
 }
diff --git a/app/Models/ContentReport.php b/app/Models/ContentReport.php
new file mode 100644
index 0000000..d9fce75
--- /dev/null
+++ b/app/Models/ContentReport.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+/**
+ * Report (something objectionable spotted by a user)
+ */
+class ContentReport extends Model
+{
+    /** Authoring user */
+    public function author()
+    {
+        return $this->belongsTo(User::class, 'author_id');
+    }
+
+    /** Authoring user */
+    public function object()
+    {
+        return $this->morphTo();
+    }
+}
diff --git a/app/Models/DataRow.php b/app/Models/DataRow.php
index 8b47458..1b01f77 100644
--- a/app/Models/DataRow.php
+++ b/app/Models/DataRow.php
@@ -4,6 +4,9 @@ namespace App\Models;
 
 use Illuminate\Database\Eloquent\Model;
 
+/**
+ * Row in a data table
+ */
 class DataRow extends Model
 {
     /** Parent data table */
diff --git a/app/Models/DataTable.php b/app/Models/DataTable.php
index 34acb71..9b73f37 100644
--- a/app/Models/DataTable.php
+++ b/app/Models/DataTable.php
@@ -4,8 +4,18 @@ namespace App\Models;
 
 use Illuminate\Database\Eloquent\Model;
 
+/**
+ * A data table object (referencing changesets and rows)
+ */
 class DataTable extends Model
 {
+    /**
+     * The attributes that should be mutated to dates.
+     *
+     * @var array
+     */
+    protected $dates = ['deleted_at'];
+
     /** Owning user */
     public function owner()
     {
@@ -13,15 +23,15 @@ class DataTable extends Model
     }
 
     /** Fork precursor */
-    public function precursor()
+    public function parentTable()
     {
-        return $this->belongsTo(DataTable::class, 'precursor_id');
+        return $this->belongsTo(DataTable::class, 'parent_table_id');
     }
 
     /** Fork descendants */
-    public function descendants()
+    public function forks()
     {
-        return $this->hasMany(DataTable::class, 'precursor_id');
+        return $this->hasMany(DataTable::class, 'parent_table_id');
     }
 
     /** Changesets */
@@ -36,15 +46,27 @@ class DataTable extends Model
         return $this->hasMany(DataRow::class);
     }
 
-    /** Changesets already merged */
-    public function appliedChangesets()
+    /** User-submitted comments */
+    public function comments()
+    {
+        return $this->hasMany(TableComment::class);
+    }
+
+    /** Users favouriting this table */
+    public function favouritingUsers()
+    {
+        return $this->belongsToMany(User::class, 'table_favourites');
+    }
+
+    /** Users to notify about comments */
+    public function discussionFollowers()
     {
-        return $this->hasMany(Changeset::class)->where('applied', true);
+        return $this->belongsToMany(User::class, 'discussion_follows');
     }
 
-    /** Changesets already merged */
-    public function pendingChangesets()
+    /** Reports of this table */
+    public function reportsOf()
     {
-        return $this->hasMany(Changeset::class)->where('applied', false);
+        return $this->morphMany(ContentReport::class, 'object');
     }
 }
diff --git a/app/Models/Notification.php b/app/Models/Notification.php
new file mode 100644
index 0000000..43efdfc
--- /dev/null
+++ b/app/Models/Notification.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+/**
+ * Notification received by a user
+ */
+class Notification extends Model
+{
+    /** Recipient user */
+    public function user()
+    {
+        return $this->belongsTo(User::class, 'user_id');
+    }
+
+    /** User who triggered this notification */
+    public function actor()
+    {
+        return $this->belongsTo(User::class, 'actor_id');
+    }
+
+    /** Notification context (what was affected) */
+    public function context()
+    {
+        return $this->morphTo();
+    }
+
+    /**
+     * Unseen notifications
+     *
+     * @param \Illuminate\Database\Eloquent\Builder $query
+     * @return \Illuminate\Database\Eloquent\Builder
+     */
+    public function scopeUnseen($query)
+    {
+        return $query->where('seen', false);
+    }
+
+    /**
+     * Seen notifications
+     *
+     * @param \Illuminate\Database\Eloquent\Builder $query
+     * @return \Illuminate\Database\Eloquent\Builder
+     */
+    public function scopeSeen($query)
+    {
+        return $query->where('seen', true);
+    }
+}
diff --git a/app/Models/TableComment.php b/app/Models/TableComment.php
new file mode 100644
index 0000000..0827132
--- /dev/null
+++ b/app/Models/TableComment.php
@@ -0,0 +1,41 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+/**
+ * Comment on a data table
+ */
+class TableComment extends Model
+{
+    /** Context data table */
+    public function dataTable()
+    {
+        return $this->belongsTo(DataTable::class);
+    }
+
+    /** Parent comment (that we reply to; can be null) */
+    public function ancestor()
+    {
+        return $this->belongsTo(TableComment::class, 'ancestor_id');
+    }
+
+    /** Replies to this comment */
+    public function replies()
+    {
+        return $this->hasMany(TableComment::class, 'ancestor_id');
+    }
+
+    /** Authoring user */
+    public function author()
+    {
+        return $this->belongsTo(User::class, 'author_id');
+    }
+
+    /** Reports of this comment */
+    public function reportsOf()
+    {
+        return $this->morphMany(ContentReport::class, 'object');
+    }
+}
diff --git a/app/Models/User.php b/app/Models/User.php
index 174c9e1..fdfb40e 100644
--- a/app/Models/User.php
+++ b/app/Models/User.php
@@ -6,6 +6,9 @@ use AdamWathan\EloquentOAuth\OAuthIdentity;
 use Illuminate\Notifications\Notifiable;
 use Illuminate\Foundation\Auth\User as Authenticatable;
 
+/**
+ * A user in the application
+ */
 class User extends Authenticatable
 {
     use Notifiable;
@@ -31,7 +34,7 @@ class User extends Authenticatable
     /** Owned tables */
     public function dataTables()
     {
-        return $this->hasMany(DataTable::class);
+        return $this->hasMany(DataTable::class, 'owner_id');
     }
 
     /** Assigned OAuth identities */
@@ -43,6 +46,42 @@ class User extends Authenticatable
     /** Assigned OAuth identities */
     public function changesets()
     {
-        return $this->hasMany(Changeset::class);
+        return $this->hasMany(Changeset::class, 'author_id');
+    }
+
+    /** Authored comments */
+    public function tableComments()
+    {
+        return $this->hasMany(TableComment::class, 'author_id');
+    }
+
+    /** User's favourite tables (personal collection) */
+    public function favouriteTables()
+    {
+        return $this->belongsToMany(DataTable::class, 'table_favourites');
+    }
+
+    /** Tables whose discussions user follows (this is similar to favourites) */
+    public function followedDiscussions()
+    {
+        return $this->belongsToMany(DataTable::class, 'discussion_follows');
+    }
+
+    /** Reports sent by this user */
+    public function authoredReports()
+    {
+        return $this->hasMany(ContentReport::class, 'author_id');
+    }
+
+    /** Reports of this user */
+    public function reportsOf()
+    {
+        return $this->morphMany(ContentReport::class, 'object');
+    }
+
+    /** Notifications for this user */
+    public function notifications()
+    {
+        return $this->hasMany(Notification::class);
     }
 }
diff --git a/database/migrations/2018_07_08_193638_create_data_tables_table.php b/database/migrations/2018_07_08_193638_create_data_tables_table.php
index 729b41c..ef28a94 100644
--- a/database/migrations/2018_07_08_193638_create_data_tables_table.php
+++ b/database/migrations/2018_07_08_193638_create_data_tables_table.php
@@ -27,7 +27,7 @@ class CreateDataTablesTable extends Migration
             $table->foreign('owner_id')->references('id')->on('users')
                 ->onDelete('cascade');
 
-            $table->foreign('precursor_id')->references('id')->on('data_tables')
+            $table->foreign('parent_table_id')->references('id')->on('data_tables')
                 ->onDelete('set null');
         });
     }
diff --git a/database/migrations/2018_07_12_185431_create_comments_table.php b/database/migrations/2018_07_12_185431_create_table_comments_table.php
similarity index 85%
rename from database/migrations/2018_07_12_185431_create_comments_table.php
rename to database/migrations/2018_07_12_185431_create_table_comments_table.php
index 5b347b0..99fc956 100644
--- a/database/migrations/2018_07_12_185431_create_comments_table.php
+++ b/database/migrations/2018_07_12_185431_create_table_comments_table.php
@@ -4,7 +4,7 @@ use Illuminate\Support\Facades\Schema;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Database\Migrations\Migration;
 
-class CreateCommentsTable extends Migration
+class CreateTableCommentsTable extends Migration
 {
     /**
      * Run the migrations.
@@ -13,7 +13,7 @@ class CreateCommentsTable extends Migration
      */
     public function up()
     {
-        Schema::create('comments', function (Blueprint $table) {
+        Schema::create('table_comments', function (Blueprint $table) {
             $table->increments('id');
             $table->timestamps();
             $table->unsignedInteger('ancestor_id')->index()->nullable();
@@ -39,6 +39,6 @@ class CreateCommentsTable extends Migration
      */
     public function down()
     {
-        Schema::dropIfExists('comments');
+        Schema::dropIfExists('table_comments');
     }
 }
diff --git a/database/migrations/2018_07_12_185840_create_favourites_table.php b/database/migrations/2018_07_12_185840_create_table_favourites_table.php
similarity index 81%
rename from database/migrations/2018_07_12_185840_create_favourites_table.php
rename to database/migrations/2018_07_12_185840_create_table_favourites_table.php
index 9eb7431..0fb7131 100644
--- a/database/migrations/2018_07_12_185840_create_favourites_table.php
+++ b/database/migrations/2018_07_12_185840_create_table_favourites_table.php
@@ -4,7 +4,7 @@ use Illuminate\Support\Facades\Schema;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Database\Migrations\Migration;
 
-class CreateFavouritesTable extends Migration
+class CreateTableFavouritesTable extends Migration
 {
     /**
      * Run the migrations.
@@ -13,7 +13,7 @@ class CreateFavouritesTable extends Migration
      */
     public function up()
     {
-        Schema::create('favourites', function (Blueprint $table) {
+        Schema::create('table_favourites', function (Blueprint $table) {
             $table->increments('id');
             $table->timestamps();
 
@@ -35,6 +35,6 @@ class CreateFavouritesTable extends Migration
      */
     public function down()
     {
-        Schema::dropIfExists('favourites');
+        Schema::dropIfExists('table_favourites');
     }
 }
diff --git a/database/migrations/2018_07_12_190830_create_notifications_table.php b/database/migrations/2018_07_12_190830_create_notifications_table.php
index 312ab73..920e4fd 100644
--- a/database/migrations/2018_07_12_190830_create_notifications_table.php
+++ b/database/migrations/2018_07_12_190830_create_notifications_table.php
@@ -16,6 +16,7 @@ class CreateNotificationsTable extends Migration
         Schema::create('notifications', function (Blueprint $table) {
             $table->increments('id');
             $table->timestamps();
+            $table->boolean('seen');
             $table->unsignedInteger('user_id')->index();
             $table->unsignedInteger('actor_id')->index()->nullable(); // who did it
             $table->string('action'); // what happened, e.g.: favourited, mentioned, forked, commented