diff --git a/tildes/tildes/models/user/user.py b/tildes/tildes/models/user/user.py
index 9a1c22d..a49a965 100644
--- a/tildes/tildes/models/user/user.py
+++ b/tildes/tildes/models/user/user.py
@@ -320,6 +320,11 @@ class User(DatabaseModel):
 
         return principals
 
+    @property
+    def is_real_user(self) -> bool:
+        """Return whether this is a "real" user (not a special-purpose internal one)."""
+        return self.user_id > 0
+
     @property
     def is_admin(self) -> bool:
         """Return whether the user has admin permissions."""
diff --git a/tildes/tildes/templates/bookmarks.jinja2 b/tildes/tildes/templates/bookmarks.jinja2
index fafb361..24f552c 100644
--- a/tildes/tildes/templates/bookmarks.jinja2
+++ b/tildes/tildes/templates/bookmarks.jinja2
@@ -1,7 +1,7 @@
 {% extends 'base_user_menu.jinja2' %}
 
 {% from 'macros/comments.jinja2' import render_single_comment with context %}
-{% from 'macros/links.jinja2' import group_linked, username_linked %}
+{% from 'macros/links.jinja2' import group_linked %}
 {% from 'macros/topics.jinja2' import render_topic_for_listing with context %}
 
 {% block title %}Bookmarks{% endblock %}
diff --git a/tildes/tildes/templates/macros/comments.jinja2 b/tildes/tildes/templates/macros/comments.jinja2
index 19a1bfc..8ae7531 100644
--- a/tildes/tildes/templates/macros/comments.jinja2
+++ b/tildes/tildes/templates/macros/comments.jinja2
@@ -4,7 +4,7 @@
 {% from 'buttons.jinja2' import post_action_toggle_button with context %}
 {% from 'datetime.jinja2' import adaptive_date_responsive %}
 {% from 'forms.jinja2' import markdown_textarea %}
-{% from 'links.jinja2' import username_linked %}
+{% from 'links.jinja2' import link_to_user %}
 {% from 'utils.jinja2' import pluralize %}
 
 {% macro render_single_comment(comment) %}
@@ -53,7 +53,7 @@
       {% endif %}
 
       {% if request.has_permission('view', comment) %}
-        {{ username_linked(comment.user.username) }}
+        {{ link_to_user(comment.user) }}
 
         {% if request.has_permission('view_author', comment.topic) and comment.topic.user == comment.user %}
           <span class="comment-user-info">
@@ -119,7 +119,7 @@
               <span class="comment-label-count">
                 {{ weight }}:
                 {% for label in comment.labels if label.name == label_name %}
-                  {{ username_linked(label.user.username) }} ({{ label.weight }}{{ ' "%s"' % label.reason if label.reason else '' }})
+                  {{ link_to_user(label.user) }} ({{ label.weight }}{{ ' "%s"' % label.reason if label.reason else '' }})
                 {% endfor %}
               </span>
             </li>
diff --git a/tildes/tildes/templates/macros/links.jinja2 b/tildes/tildes/templates/macros/links.jinja2
index fdbd725..710dfa9 100644
--- a/tildes/tildes/templates/macros/links.jinja2
+++ b/tildes/tildes/templates/macros/links.jinja2
@@ -1,11 +1,11 @@
 {# Copyright (c) 2018 Tildes contributors <code@tildes.net> #}
 {# SPDX-License-Identifier: AGPL-3.0-or-later #}
 
-{% macro username_linked(username) -%}
-  {% if username != "unknown user" %}
-    <a href="/user/{{ username }}" class="link-user">{{ username }}</a>
+{% macro link_to_user(user) -%}
+  {% if user.is_real_user %}
+    <a href="/user/{{ user.username }}" class="link-user">{{ user.username }}</a>
   {% else %}
-    {{ username }}
+    {{ user.username }}
   {% endif %}
 {%- endmacro %}
 
diff --git a/tildes/tildes/templates/macros/messages.jinja2 b/tildes/tildes/templates/macros/messages.jinja2
index 2896e1d..ab47535 100644
--- a/tildes/tildes/templates/macros/messages.jinja2
+++ b/tildes/tildes/templates/macros/messages.jinja2
@@ -2,7 +2,7 @@
 {# SPDX-License-Identifier: AGPL-3.0-or-later #}
 
 {% from 'macros/datetime.jinja2' import adaptive_date_responsive %}
-{% from 'macros/links.jinja2' import username_linked %}
+{% from 'macros/links.jinja2' import link_to_user %}
 
 {% macro render_message(message) %}
   {% if message.sender == request.user %}
@@ -12,7 +12,7 @@
   {% endif %}
 
     <header>
-      {{ username_linked(message.sender.username) }}
+      {{ link_to_user(message.sender) }}
       {{ adaptive_date_responsive(message.created_time) }}
     </header>
 
diff --git a/tildes/tildes/templates/macros/topics.jinja2 b/tildes/tildes/templates/macros/topics.jinja2
index 7e6e67f..f950315 100644
--- a/tildes/tildes/templates/macros/topics.jinja2
+++ b/tildes/tildes/templates/macros/topics.jinja2
@@ -2,7 +2,7 @@
 {# SPDX-License-Identifier: AGPL-3.0-or-later #}
 
 {% from 'macros/datetime.jinja2' import adaptive_date_responsive %}
-{% from 'macros/links.jinja2' import group_linked, username_linked %}
+{% from 'macros/links.jinja2' import group_linked, link_to_user %}
 {% from 'utils.jinja2' import pluralize %}
 
 {% macro render_topic_for_listing(topic, show_group=False, rank=None) %}
@@ -90,7 +90,7 @@
 
       <div class="topic-info-source"
       {% if topic.is_user_treated_as_source %}
-        aria-label="Posted by">{{ username_linked(topic.user.username) }}
+        aria-label="Posted by">{{ link_to_user(topic.user) }}
       {% else %}
         aria-label="Link source">
         {% if topic.is_link_type %}
diff --git a/tildes/tildes/templates/messages.jinja2 b/tildes/tildes/templates/messages.jinja2
index f969de7..575e318 100644
--- a/tildes/tildes/templates/messages.jinja2
+++ b/tildes/tildes/templates/messages.jinja2
@@ -4,7 +4,7 @@
 {% extends 'base_user_menu.jinja2' %}
 
 {% from 'macros/datetime.jinja2' import adaptive_date_responsive %}
-{% from 'macros/links.jinja2' import username_linked %}
+{% from 'macros/links.jinja2' import link_to_user %}
 
 {% block title %}Message Inbox{% endblock %}
 
@@ -30,7 +30,7 @@
       <td class="message-list-subject">
         <a href="{{ request.route_url('message_conversation', conversation_id36=conversation.conversation_id36) }}">{{ conversation.subject }}</a>
       </td>
-      <td>{{ username_linked(conversation.other_user(request.user).username) }}</td>
+      <td>{{ link_to_user(conversation.other_user(request.user)) }}</td>
       <td class="text-right">{{ adaptive_date_responsive(conversation.last_activity_time) }}</td>
       <td class="text-right">{{ conversation.num_replies + 1 }}</td>
     </tr>
diff --git a/tildes/tildes/templates/notifications_unread.jinja2 b/tildes/tildes/templates/notifications_unread.jinja2
index 4c1dd33..bdb5f0b 100644
--- a/tildes/tildes/templates/notifications_unread.jinja2
+++ b/tildes/tildes/templates/notifications_unread.jinja2
@@ -4,7 +4,7 @@
 {% extends 'base_user_menu.jinja2' %}
 
 {% from 'macros/comments.jinja2' import comment_label_options_template, comment_reply_template, render_single_comment with context %}
-{% from 'macros/links.jinja2' import group_linked, username_linked %}
+{% from 'macros/links.jinja2' import group_linked %}
 
 {% block title %}Unread notifications{% endblock %}
 
diff --git a/tildes/tildes/templates/topic.jinja2 b/tildes/tildes/templates/topic.jinja2
index b1251fa..c093ef1 100644
--- a/tildes/tildes/templates/topic.jinja2
+++ b/tildes/tildes/templates/topic.jinja2
@@ -8,7 +8,7 @@
 {% from 'macros/datetime.jinja2' import adaptive_date_responsive, time_ago %}
 {% from 'macros/forms.jinja2' import markdown_textarea %}
 {% from 'macros/groups.jinja2' import group_segmented_link %}
-{% from 'macros/links.jinja2' import group_linked, username_linked %}
+{% from 'macros/links.jinja2' import group_linked, link_to_user %}
 {% from 'macros/topics.jinja2' import topic_voting with context %}
 {% from 'macros/utils.jinja2' import pluralize %}
 
@@ -37,7 +37,7 @@
   <h1>{{ topic.title }}</h1>
   <div class="topic-full-byline">Posted {{ adaptive_date_responsive(topic.created_time) }} by
     {% if request.has_permission('view_author', topic) %}
-      {{ username_linked(topic.user.username) }}
+      {{ link_to_user(topic.user) }}
     {% else %}
       unknown user
     {% endif %}
@@ -288,7 +288,7 @@
             {% if entry.user == topic.user and not request.has_permission('view_author', topic) %}
               Unknown user
             {% else %}
-              {{ username_linked(entry.user) }}
+              {{ link_to_user(entry.user) }}
             {% endif %}
             {{ entry }}
             <span class="topic-log-entry-time">({{ time_ago(entry.event_time, abbreviate=True) }})</span>
diff --git a/tildes/tildes/templates/user.jinja2 b/tildes/tildes/templates/user.jinja2
index 407e613..22bc3f8 100644
--- a/tildes/tildes/templates/user.jinja2
+++ b/tildes/tildes/templates/user.jinja2
@@ -4,7 +4,7 @@
 {% extends 'base_user_menu.jinja2' %}
 
 {% from 'macros/comments.jinja2' import comment_label_options_template, comment_reply_template, render_single_comment with context %}
-{% from 'macros/links.jinja2' import group_linked, username_linked %}
+{% from 'macros/links.jinja2' import group_linked %}
 {% from 'macros/topics.jinja2' import render_topic_for_listing with context %}
 
 {% block title %}User: {{ user.username }}{% endblock %}