diff --git a/website/chat.py b/website/chat.py
index 89d63e0..2d3e40e 100644
--- a/website/chat.py
+++ b/website/chat.py
@@ -12,7 +12,7 @@ from website.constants import BROADCASTER_TOKEN, MESSAGE_MAX_LENGTH, CHAT_MAX_ST
 
 from pprint import pprint
 
-messages = deque()
+messages = deque() # messages are stored from most recent on the left to least recent on the right
 captchas = {}
 viewers = viewership.viewers
 nonces = set()
@@ -72,7 +72,8 @@ def comment(text, token, c_response, c_token, nonce):
                                          'id': f'{token}-{secrets.token_hex(4)}',
                                          'hidden': False,
                                          'time': dt.strftime('%H:%M'),
-                                         'date': dt.strftime('%F %T')})
+                                         'timestamp': dt.strftime('%F %T'),
+                                         'date': dt.strftime('%F')})
                     viewers[token]['last_comment'] = now
                     viewers[token]['recent_comments'].append(now)
                     viewers[token]['verified'] = True
@@ -138,3 +139,50 @@ def set_tripcode(password, token):
 def remove_tripcode(token):
     viewers[token]['tripcode'] = tripcode.default()
     return N_APPEAR_OK, True
+
+def decorate(messages):
+    '''
+    add extra stuff to a list of messages, e.g. date, chat command responses
+    '''
+    def _is_visible(message):
+        # uncomment the end part once the broadcaster can see hidden comments
+        return not message['hidden'] # or token == BROADCASTER_TOKEN
+
+    first_visible_message = None
+    final_visible_message = None
+    for message in messages:
+        if _is_visible(message):
+            final_visible_message = message
+            break
+    messages.reverse()
+    for message in messages:
+        if _is_visible(message):
+            first_visible_message = message
+            break
+
+    # if there are no messages, do nothing
+    if first_visible_message == None or final_visible_message == None:
+        return
+
+    # TODO: chat commands e.g. !uptime; try to make it so responses always follow the message with the command, so not split over a date separator
+
+    # add date at the top if necessary
+    if first_visible_message['date'] != final_visible_message['date']:
+        messages.insert(0, {'special': 'date', 'content': first_visible_message['date']})
+
+    # add dates between messages that cross over a day boundary
+    to_insert = []
+    previous_message = None
+    for index, message in enumerate(messages):
+        if message.get('special'):
+            continue
+        if previous_message and message['date'] != previous_message['date']:
+            to_insert.append(index)
+        previous_message = message
+
+    to_insert.reverse()
+    for index in to_insert:
+        messages.insert(index, {'special': 'date', 'content': messages[index]['date']})
+
+    # revert back to original ordering
+    messages.reverse()
diff --git a/website/routes.py b/website/routes.py
index b0d4a58..ad5d320 100644
--- a/website/routes.py
+++ b/website/routes.py
@@ -151,6 +151,8 @@ def chat_iframe():
         messages = (message for message in chat.messages if not message['hidden'])
         messages = zip(messages, range(CHAT_SCROLLBACK)) # show at most CHAT_SCROLLBACK messages
         messages = [message for message, _ in messages]
+
+    chat.decorate(messages)
     return render_template('chat-iframe.html',
                            token=token,
                            messages=messages,
@@ -177,8 +179,9 @@ def heartbeat():
                  'title': stream.get_title(),
                  'start_abs': start_abs if online else None,
                  'start_rel': start_rel if online else None}
-    if token in viewership.video_was_corrupted:
-        response['corrupted'] = True
+    # commented out because we should be able to tell if we're not receiving the stream already
+#    if token in viewership.video_was_corrupted:
+#        response['corrupted'] = True
 
     return response
 
diff --git a/website/templates/chat-iframe.html b/website/templates/chat-iframe.html
index 851879c..d056ba3 100644
--- a/website/templates/chat-iframe.html
+++ b/website/templates/chat-iframe.html
@@ -12,6 +12,7 @@
           .reverse {direction: rtl;}
  
           .comment {color: white;padding:4px 0;margin-top:-4px;margin-bottom:calc(-4px + 0.375em);overflow:hidden;}
+          .date {color:gray;font-size:75%;text-align:center;border-bottom:1px solid #333;margin:0.5em 0 0.75em 0;}
 
           .name {font-weight: bold;unicode-bidi: isolate;}
           sup {margin: 0 -0.25em 0 0.125em;font-size: 90%;font-family:monospace;}
@@ -91,22 +92,26 @@
 
     <!-- TODO: mobile tooltip / title -->
     {% for message in messages %}
-        <div class="comment rotate">
-            {% if not message['hidden'] %}
-                {% if broadcaster %}
-                    <input type="checkbox" name="message_id[]" value="{{ message['id'] }}">
+        {% if message.get('special') == 'date' %}
+            <div class="date rotate">{{ message['content'] }}</div>
+         {% else %}
+            <div class="comment rotate">
+                {% if not message['hidden'] %}
+                    {% if broadcaster %}
+                        <input type="checkbox" name="message_id[]" value="{{ message['id'] }}">
+                    {% endif %}
+                    <span class="time" title="{{ message['timestamp'] }}">{{ message['time'] }}</span
+                    {% if message['viewer']['broadcaster'] %}
+                        ><span class="camera" title="Broadcaster">🎥</span
+                    {% endif %}
+                    ><span class="name" style="color:#{{ message['viewer']['colour'].hex() }};">{{ RE_WHITESPACE.sub(chr(160), message['viewer']['nickname'] or default_nickname(message['viewer']['token'])) }}{% with tag = message['viewer']['nickname'] == None and not message['viewer']['broadcaster'] %}{% if tag %}<sup>{{ message['viewer']['tag'] }}</sup>{% endif %}</span
+                    {% if message['viewer']['tripcode']['string'] %}{% if tag %}><span style="margin-right:0.125em;"></span{% endif %}
+                        ><div class="tripcode" style="background-color:#{{ message['viewer']['tripcode']['background_colour'].hex() }};color:#{{ message['viewer']['tripcode']['foreground_colour'].hex() }};">{{ message['viewer']['tripcode']['string'] }}</div
+                    {% endif %}{% endwith %}
+                    ><span class="message">{{ message['text'] }}</span>
                 {% endif %}
-                <span class="time" title="{{ message['date'] }}">{{ message['time'] }}</span
-                {% if message['viewer']['broadcaster'] %}
-                    ><span class="camera" title="Broadcaster">🎥</span
-                {% endif %}
-                ><span class="name" style="color:#{{ message['viewer']['colour'].hex() }};">{{ RE_WHITESPACE.sub(chr(160), message['viewer']['nickname'] or default_nickname(message['viewer']['token'])) }}{% with tag = message['viewer']['nickname'] == None and not message['viewer']['broadcaster'] %}{% if tag %}<sup>{{ message['viewer']['tag'] }}</sup>{% endif %}</span
-                {% if message['viewer']['tripcode']['string'] %}{% if tag %}><span style="margin-right:0.125em;"></span{% endif %}
-                    ><div class="tripcode" style="background-color:#{{ message['viewer']['tripcode']['background_colour'].hex() }};color:#{{ message['viewer']['tripcode']['foreground_colour'].hex() }};">{{ message['viewer']['tripcode']['string'] }}</div
-                {% endif %}{% endwith %}
-                ><span class="message">{{ message['text'] }}</span>
-            {% endif %}
-        </div>
+            </div>
+        {% endif %}
     {% endfor %}
 
 {% if broadcaster %}
diff --git a/website/utils/colour.py b/website/utils/colour.py
index d6d7846..92f876d 100644
--- a/website/utils/colour.py
+++ b/website/utils/colour.py
@@ -13,7 +13,7 @@ def _distance_sq(c1, c2):
 
 def _gen_colour(seed, background=BACKGROUND_COLOUR):
     '''
-    Returns a colour that with sufficient contrast to the background colour
+    Returns a colour with sufficient contrast to the background colour
     '''
     while True:
         seed = hashlib.sha256(seed).digest()
@@ -24,14 +24,14 @@ def _gen_colour(seed, background=BACKGROUND_COLOUR):
 
 def gen_colour(seed, background=BACKGROUND_COLOUR, *avoid):
     '''
-    Returns a colour that with sufficient contrast to the background colour
+    Returns a colour with sufficient contrast to the background colour
     Tries to make the colour contrast with all the colours in `avoid`
     This function hasn't been analysed for efficiency or anything
     '''
     best_colour, best_score = None, None
     for _ in range(16384):
         colour = _gen_colour(seed, background)
-        score = float('inf') if len(avoid) == 0 else sum(_distance_sq(colour, c) for c in avoid) / len(avoid)
+        score = float('inf') if len(avoid) == 0 else sum(_contrast(colour, c) for c in avoid) / len(avoid)
         if colour in avoid:
             score = float('-inf')
         if 1.8 < score:
@@ -45,9 +45,9 @@ def gen_colour(seed, background=BACKGROUND_COLOUR, *avoid):
 #    tag = ((colour[2] & 0xf0) >> 4) | (colour[1] & 0xf0) | ((colour[0] & 0xf0) << 4)
 #    return f'#{tag:03x}'
 
-def tag(colour, length=3):
+def tag(token, length=3):
     '''
-    Generates a deterministic pseudorandom tag from a given colour
+    Generates a deterministic pseudorandom tag from a given token
     '''
-    digest = hashlib.sha256(colour).digest()
+    digest = hashlib.sha256(token.encode()).digest()
     return f'#{digest.hex()[:length]}'
diff --git a/website/viewership.py b/website/viewership.py
index 91ffb76..fc6cd10 100644
--- a/website/viewership.py
+++ b/website/viewership.py
@@ -38,7 +38,7 @@ def setdefault(token):
                       'banned': False,
                       'tripcode': tripcode.default(),
                       'broadcaster': False}
-    viewers[token]['tag'] = colour.tag(viewers[token]['colour'])
+    viewers[token]['tag'] = colour.tag(token)
     if token == BROADCASTER_TOKEN:
         viewers[token]['broadcaster'] = True
         viewers[token]['colour'] = BROADCASTER_COLOUR