diff --git a/app/Community/Actions/ReplaceUserShortcodesWithUsernamesAction.php b/app/Community/Actions/ReplaceUserShortcodesWithUsernamesAction.php
new file mode 100644
index 0000000000..bae7154b39
--- /dev/null
+++ b/app/Community/Actions/ReplaceUserShortcodesWithUsernamesAction.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Community\Actions;
+
+use App\Models\User;
+
+class ReplaceUserShortcodesWithUsernamesAction
+{
+    public function execute(string $messageBody): string
+    {
+        // Extract all user IDs from the message.
+        // We'll do a single query to the users table to avoid an N+1 waterfall.
+        preg_match_all('/\[user=(\d+)\]/', $messageBody, $matches);
+        $userIds = $matches[1] ?? [];
+
+        if (empty($userIds)) {
+            return $messageBody;
+        }
+
+        $users = User::whereIn('ID', $userIds)->get()->keyBy('ID');
+
+        // Replace each shortcode with the corresponding username.
+        return preg_replace_callback('/\[user=(\d+)\]/', function ($matches) use ($users) {
+            $userId = $matches[1];
+            $user = $users->get($userId);
+
+            return '[user=' . ($user ? $user->username : $userId) . ']';
+        }, $messageBody);
+    }
+}
diff --git a/app/Community/Listeners/NotifyMessageThreadParticipants.php b/app/Community/Listeners/NotifyMessageThreadParticipants.php
index f9bdb1cc47..bac314dbd8 100644
--- a/app/Community/Listeners/NotifyMessageThreadParticipants.php
+++ b/app/Community/Listeners/NotifyMessageThreadParticipants.php
@@ -11,6 +11,7 @@
 use App\Models\MessageThread;
 use App\Models\MessageThreadParticipant;
 use App\Models\User;
+use App\Support\Shortcode\Shortcode;
 use GuzzleHttp\Client;
 use Illuminate\Support\Arr;
 use Illuminate\Support\Facades\DB;
@@ -73,6 +74,8 @@ private function forwardToDiscord(
         MessageThread $messageThread,
         Message $message
     ): void {
+        $message->body = Shortcode::stripAndClamp($message->body);
+
         $inboxConfig = config('services.discord.inbox_webhook.' . $userTo->username);
         $webhookUrl = $inboxConfig['url'] ?? null;
 
diff --git a/app/Community/Livewire/Forms/ForumTopicCommentForm.php b/app/Community/Livewire/Forms/ForumTopicCommentForm.php
index 9716b434d1..0f4b56a852 100644
--- a/app/Community/Livewire/Forms/ForumTopicCommentForm.php
+++ b/app/Community/Livewire/Forms/ForumTopicCommentForm.php
@@ -4,6 +4,7 @@
 
 namespace App\Community\Livewire\Forms;
 
+use App\Community\Actions\ReplaceUserShortcodesWithUsernamesAction;
 use App\Models\ForumTopicComment;
 use App\Support\Rules\ContainsRegularCharacter;
 use Illuminate\Foundation\Auth\Access\AuthorizesRequests;
@@ -24,7 +25,11 @@ class ForumTopicCommentForm extends Form
     public function setForumTopicComment(ForumTopicComment $forumTopicComment): void
     {
         $this->forumTopicComment = $forumTopicComment;
-        $this->body = $forumTopicComment->body;
+
+        // "[user=1]" -> "[user=Scott]"
+        $this->body = (
+            new ReplaceUserShortcodesWithUsernamesAction()
+        )->execute($this->forumTopicComment->body);
     }
 
     public function update(): RedirectResponse|Redirector
diff --git a/app/Helpers/util/mail.php b/app/Helpers/util/mail.php
index c47bb809f0..ce233a1174 100644
--- a/app/Helpers/util/mail.php
+++ b/app/Helpers/util/mail.php
@@ -3,6 +3,7 @@
 use App\Community\Enums\ArticleType;
 use App\Enums\Permissions;
 use App\Models\User;
+use App\Support\Shortcode\Shortcode;
 use Aws\CommandPool;
 use Illuminate\Contracts\Mail\Mailer as MailerContract;
 use Illuminate\Mail\Mailer;
@@ -364,6 +365,7 @@ function SendPrivateMessageEmail(
     }
 
     $content = stripslashes(nl2br($contentIn));
+    $content = Shortcode::stripAndClamp($content);
 
     // Also used for Generic text:
     $emailTitle = "New Private Message from $fromUser";
diff --git a/tests/Feature/Community/Actions/ReplaceUserShortcodesWithUsernamesActionTest.php b/tests/Feature/Community/Actions/ReplaceUserShortcodesWithUsernamesActionTest.php
new file mode 100644
index 0000000000..656e8c93af
--- /dev/null
+++ b/tests/Feature/Community/Actions/ReplaceUserShortcodesWithUsernamesActionTest.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Feature\Community\Actions;
+
+use App\Community\Actions\ReplaceUserShortcodesWithUsernamesAction;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class ReplaceUserShortcodesWithUsernamesActionTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function testItReplacesUserIds(): void
+    {
+        // Arrange
+        User::factory()->create(['ID' => 100, 'User' => 'Scott']);
+        User::factory()->create(['ID' => 101, 'User' => 'Batman']);
+
+        $messageBody = "[user=100] might actually be [user=101].";
+
+        // Act
+        $result = (new ReplaceUserShortcodesWithUsernamesAction())->execute($messageBody);
+
+        // Assert
+        $this->assertEquals("[user=Scott] might actually be [user=Batman].", $result);
+    }
+}