diff --git a/packages/backend/src/server/web/views/announcement.pug b/packages/backend/src/server/web/views/announcement.pug
index 7a4052e8a4..06cea4e57b 100644
--- a/packages/backend/src/server/web/views/announcement.pug
+++ b/packages/backend/src/server/web/views/announcement.pug
@@ -7,15 +7,3 @@ block vars
 
 block title
 	= `${title} | ${instanceName}`
-
-block desc
-	meta(name='description' content=description)
-
-block og
-	meta(property='og:type'        content='article')
-	meta(property='og:title'       content= title)
-	meta(property='og:description' content= description)
-	meta(property='og:url'         content= url)
-	if announcement.imageUrl
-		meta(property='og:image' content=announcement.imageUrl)
-		meta(property='twitter:card' content='summary_large_image')
diff --git a/packages/backend/src/server/web/views/channel.pug b/packages/backend/src/server/web/views/channel.pug
index c514025e0b..701b88c8c4 100644
--- a/packages/backend/src/server/web/views/channel.pug
+++ b/packages/backend/src/server/web/views/channel.pug
@@ -6,14 +6,3 @@ block vars
 
 block title
 	= `${title} | ${instanceName}`
-
-block desc
-	meta(name='description' content= channel.description)
-
-block og
-	meta(property='og:type'        content='article')
-	meta(property='og:title'       content= title)
-	meta(property='og:description' content= channel.description)
-	meta(property='og:url'         content= url)
-	meta(property='og:image'       content= channel.bannerUrl)
-	meta(property='twitter:card'   content='summary')
diff --git a/packages/backend/src/server/web/views/clip.pug b/packages/backend/src/server/web/views/clip.pug
index 5a0018803a..6510232266 100644
--- a/packages/backend/src/server/web/views/clip.pug
+++ b/packages/backend/src/server/web/views/clip.pug
@@ -8,17 +8,6 @@ block vars
 block title
 	= `${title} | ${instanceName}`
 
-block desc
-	meta(name='description' content= clip.description)
-
-block og
-	meta(property='og:type'        content='article')
-	meta(property='og:title'       content= title)
-	meta(property='og:description' content= clip.description)
-	meta(property='og:url'         content= url)
-	meta(property='og:image'       content= avatarUrl)
-	meta(property='twitter:card'   content='summary')
-
 block meta
 	if profile.noCrawle
 		meta(name='robots' content='noindex')
diff --git a/packages/backend/src/server/web/views/flash.pug b/packages/backend/src/server/web/views/flash.pug
index 1549aa7906..02501b3767 100644
--- a/packages/backend/src/server/web/views/flash.pug
+++ b/packages/backend/src/server/web/views/flash.pug
@@ -8,17 +8,6 @@ block vars
 block title
 	= `${title} | ${instanceName}`
 
-block desc
-	meta(name='description' content= flash.summary)
-
-block og
-	meta(property='og:type'        content='article')
-	meta(property='og:title'       content= title)
-	meta(property='og:description' content= flash.summary)
-	meta(property='og:url'         content= url)
-	meta(property='og:image'       content= avatarUrl)
-	meta(property='twitter:card'   content='summary')
-
 block meta
 	if profile.noCrawle
 		meta(name='robots' content='noindex')
diff --git a/packages/backend/src/server/web/views/gallery-post.pug b/packages/backend/src/server/web/views/gallery-post.pug
index 9ae25d9ac8..aba5a8c1ce 100644
--- a/packages/backend/src/server/web/views/gallery-post.pug
+++ b/packages/backend/src/server/web/views/gallery-post.pug
@@ -8,21 +8,6 @@ block vars
 block title
 	= `${title} | ${instanceName}`
 
-block desc
-	meta(name='description' content= post.description)
-
-block og
-	meta(property='og:type'        content='article')
-	meta(property='og:title'       content= title)
-	meta(property='og:description' content= post.description)
-	meta(property='og:url'         content= url)
-	if post.isSensitive
-		meta(property='og:image'     content= avatarUrl)
-		meta(property='twitter:card' content='summary')
-	else
-		meta(property='og:image'       content= post.files[0].thumbnailUrl)
-		meta(property='twitter:card'   content='summary_large_image')
-
 block meta
 	if user.host || profile.noCrawle
 		meta(name='robots' content='noindex')
diff --git a/packages/backend/src/server/web/views/note.pug b/packages/backend/src/server/web/views/note.pug
index 53cff6bcd3..3ff4005915 100644
--- a/packages/backend/src/server/web/views/note.pug
+++ b/packages/backend/src/server/web/views/note.pug
@@ -11,31 +11,6 @@ block vars
 block title
 	= `${title} | ${instanceName}`
 
-block desc
-	meta(name='description' content= summary)
-
-block og
-	meta(property='og:type'        content='article')
-	meta(property='og:title'       content= title)
-	meta(property='og:description' content= summary)
-	meta(property='og:url'         content= url)
-	if videos.length
-		each video in videos
-			meta(property='og:video:url'        content= video.url)
-			meta(property='og:video:secure_url' content= video.url)
-			meta(property='og:video:type'       content= video.type)
-			meta(property='og:image'            content= video.thumbnailUrl)
-			// FIXME: add width and height
-			// FIXME: add embed player for Twitter
-	if images.length
-		meta(property='twitter:card' content='summary_large_image')
-		each image in images
-			meta(property='og:image'     content= image.url)
-	else if !videos.length
-		meta(property='twitter:card' content='summary')
-		meta(property='og:image'     content= avatarUrl)
-
-
 block meta
 	if user.host || isRenote || profile.noCrawle
 		meta(name='robots' content='noindex')
diff --git a/packages/backend/src/server/web/views/page.pug b/packages/backend/src/server/web/views/page.pug
index 03c50eca8a..31abaf2c78 100644
--- a/packages/backend/src/server/web/views/page.pug
+++ b/packages/backend/src/server/web/views/page.pug
@@ -8,17 +8,6 @@ block vars
 block title
 	= `${title} | ${instanceName}`
 
-block desc
-	meta(name='description' content= page.summary)
-
-block og
-	meta(property='og:type'        content='article')
-	meta(property='og:title'       content= title)
-	meta(property='og:description' content= page.summary)
-	meta(property='og:url'         content= url)
-	meta(property='og:image'       content= page.eyeCatchingImage ? page.eyeCatchingImage.thumbnailUrl : avatarUrl)
-	meta(property='twitter:card'   content= page.eyeCatchingImage ? 'summary_large_image' : 'summary')
-
 block meta
 	if profile.noCrawle
 		meta(name='robots' content='noindex')
diff --git a/packages/backend/src/server/web/views/user.pug b/packages/backend/src/server/web/views/user.pug
index 2b0a7bab5c..88d2c843e1 100644
--- a/packages/backend/src/server/web/views/user.pug
+++ b/packages/backend/src/server/web/views/user.pug
@@ -7,17 +7,6 @@ block vars
 block title
 	= `${title} | ${instanceName}`
 
-block desc
-	meta(name='description' content= profile.description)
-
-block og
-	meta(property='og:type'        content='blog')
-	meta(property='og:title'       content= title)
-	meta(property='og:description' content= profile.description)
-	meta(property='og:url'         content= url)
-	meta(property='og:image'       content= avatarUrl)
-	meta(property='twitter:card'   content='summary')
-
 block meta
 	if user.host || profile.noCrawle
 		meta(name='robots' content='noindex')
diff --git a/packages/frontend/src/components/global/userIdWatermark.vue b/packages/frontend/src/components/global/userIdWatermark.vue
new file mode 100644
index 0000000000..3e00fc6320
--- /dev/null
+++ b/packages/frontend/src/components/global/userIdWatermark.vue
@@ -0,0 +1,69 @@
+<script setup lang="ts">
+import { $i } from "@/i.js";
+import { computed, onMounted } from 'vue';
+
+const generateRandomClass = () => {
+	const chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
+	let result = '';
+	for (let i = 0; i < 8; i++) {
+		result += chars.charAt(Math.floor(Math.random() * chars.length));
+	}
+	return result;
+};
+
+const gridClass = computed(() => generateRandomClass());
+const itemClass = computed(() => generateRandomClass());
+
+onMounted(() => {
+	const style = document.createElement('style');
+	style.textContent = `
+		.${gridClass.value} {
+			position: fixed;
+			top: 0;
+			left: 0;
+			width: 100vw;
+			height: 100vh;
+			display: grid;
+			grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
+			grid-template-rows: repeat(auto-fill, minmax(20px, 1fr));
+			gap: 20px;
+			padding: 20px;
+			pointer-events: none;
+			z-index: 999999999;
+			overflow: hidden;
+		}
+
+		.${itemClass.value} {
+			display: flex;
+			align-items: center;
+			justify-content: center;
+			color: color-mix(
+				in srgb,
+				var(--MI_THEME-fg) 0.4%,
+				transparent
+			) !important;
+			font-size: 12px;
+			font-family: monospace;
+			word-break: break-all;
+			text-align: center;
+			user-select: none;
+		}
+	`;
+	document.head.appendChild(style);
+});
+</script>
+
+<template>
+	<div v-if="$i" :class="gridClass">
+		<div v-for="n in 600" :key="n" :class="itemClass">
+			{{ $i.id }}
+		</div>
+	</div>
+	<div v-else :class="gridClass">
+		<div v-for="n in 600" :key="n" :class="itemClass">
+			not signed in
+		</div>
+	</div>
+</template>
+
+
diff --git a/packages/frontend/src/ui/_common_/common.vue b/packages/frontend/src/ui/_common_/common.vue
index 9d748d9331..739c4576a7 100644
--- a/packages/frontend/src/ui/_common_/common.vue
+++ b/packages/frontend/src/ui/_common_/common.vue
@@ -4,6 +4,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 -->
 
 <template>
+<userIdWatermark/>
 <Transition
 	:enterActiveClass="prefer.s.animation ? $style.transition_menuDrawerBg_enterActive : ''"
 	:leaveActiveClass="prefer.s.animation ? $style.transition_menuDrawerBg_leaveActive : ''"
@@ -115,6 +116,7 @@ import { prefer } from '@/preferences.js';
 import { globalEvents } from '@/events.js';
 import XDrawerMenu from '@/ui/_common_/navbar-for-mobile.vue';
 import SkTransitionGroup from '@/components/SkTransitionGroup.vue';
+import userIdWatermark from '@/components/global/userIdWatermark.vue';
 
 const XStreamIndicator = defineAsyncComponent(() => import('./stream-indicator.vue'));
 const XUpload = defineAsyncComponent(() => import('./upload.vue'));