Use less characters to describe the same meaning

public/language/ja/footer.json

@@ -1,6 +1,6 @@
 {
-    "stats.online": "オンライン",
-    "stats.users": "ユーザー",
+    "stats.online": "利用者",
+    "stats.users": "登録",
     "stats.topics": "スレッド",
     "stats.posts": "ポスト",
     "success": "成功"