diff --git a/css/style.css b/css/style.css
index 2de6a7af2..11916e177 100644
--- a/css/style.css
+++ b/css/style.css
@@ -787,6 +787,7 @@ a.hide-announcement {
   min-width: 100%;
   overflow: hidden;
   white-space: nowrap;
+  position: relative;
   -webkit-user-select: none;
   -moz-user-select: none;
   user-select: none;
diff --git a/lib/$.coffee b/lib/$.coffee
index 801899dc6..939c1577e 100644
--- a/lib/$.coffee
+++ b/lib/$.coffee
@@ -288,8 +288,7 @@ do ->
       delete timeout[area]
     items[area] = {}
 
-  setAll = $.debounce $.SECOND, ->
-    setArea 'local'
+  setSync = $.debounce $.SECOND, ->
     setArea 'sync'
 
   $.set = (key, val) ->
@@ -300,7 +299,8 @@ do ->
     for key in $.localKeys when key of items.sync
       items.local[key] = items.sync[key]
       delete items.sync[key]
-    setAll()
+    setArea 'local'
+    setSync()
 
   $.clear = (cb) ->
     items.local = {}
diff --git a/src/General/DataBoard.coffee b/src/General/DataBoard.coffee
index 2aab44b17..d82ff1b65 100644
--- a/src/General/DataBoard.coffee
+++ b/src/General/DataBoard.coffee
@@ -58,15 +58,14 @@ class DataBoard
     val or defaultValue
 
   clean: ->
-    for boardID, val of @data.boards
-      @deleteIfEmpty {boardID}
-
     now = Date.now()
-    if (@data.lastChecked or 0) < now - 2 * $.HOUR
-      @data.lastChecked = now
-      for boardID of @data.boards
-        @ajaxClean boardID
+    return if (@data.lastChecked or 0) > now - 2 * $.HOUR
 
+    for boardID of @data.boards
+      @deleteIfEmpty {boardID}
+      @ajaxClean boardID if boardID of @data.boards
+
+    @data.lastChecked = now
     @save()
   ajaxClean: (boardID) ->
     $.cache "//a.4cdn.org/#{boardID}/threads.json", (e) =>
@@ -76,12 +75,14 @@ class DataBoard
       board   = @data.boards[boardID]
       threads = {}
       for page in e.target.response
-        for thread in page.threads
-          if thread.no of board
-            threads[thread.no] = board[thread.no]
-      @data.boards[boardID] = threads
-      @deleteIfEmpty {boardID}
-      @save()
+        for thread in page.threads when thread.no of board
+          threads[thread.no] = board[thread.no]
+      count = Object.keys(threads).length
+      return if count is Object.keys(board).length # Nothing changed.
+      if count
+        @set {boardID, val: threads}
+      else
+        @delete {boardID}
 
   onSync: (data) =>
     @data = data or boards: {}
diff --git a/src/Monitoring/Unread.coffee b/src/Monitoring/Unread.coffee
index 8e13c463e..39fc9fce9 100644
--- a/src/Monitoring/Unread.coffee
+++ b/src/Monitoring/Unread.coffee
@@ -139,7 +139,7 @@ Unread =
     Unread.readArray Unread.postsQuotingYou
     Unread.update() if e
 
-  saveLastReadPost: ->
+  saveLastReadPost: <% if (type === 'crx') { %>$.debounce 5 * $.SECOND,<% } %> ->
     return if Unread.thread.isDead
     Unread.db.set
       boardID:  Unread.thread.board.ID