diff --git a/src/chrome/content/itsalltext.js b/src/chrome/content/itsalltext.js
index 4d7d14d..f620c25 100644
--- a/src/chrome/content/itsalltext.js
+++ b/src/chrome/content/itsalltext.js
@@ -119,6 +119,7 @@ var ItsAllText = function () {
             extensions:         'Char',
             hotkey:             'Char',
             tracker_id:         'Char',
+            blacklist_domains:  'Char',
         },
 
         /**
diff --git a/src/chrome/content/monitor.js b/src/chrome/content/monitor.js
index b2b7af0..c90a433 100644
--- a/src/chrome/content/monitor.js
+++ b/src/chrome/content/monitor.js
@@ -252,10 +252,33 @@ Monitor.prototype.isHTML = function (doc) {
     is_html = (contentType == 'text/html' ||
                contentType == 'text/xhtml' ||
                contentType == 'application/xhtml+xml');
+
+    var blacklisted_domains = itsalltext.preferences.blacklist_domains.split("\n");
+    var pattern,
+        domain_is_blacklisted = false;
+    for(var i=0, len=blacklisted_domains.length; i<len; i++)
+    {
+        pattern = new RegExp( blacklisted_domains[i] );
+        if( pattern.test( doc.domain ) )
+        {
+            domain_is_blacklisted = true;
+            break;
+        }
+    }
+
+    /*
+    var console = Cc["@mozilla.org/consoleservice;1"].getService(Ci.nsIConsoleService);
+    if(domain_is_blacklisted)
+    {
+        console.logStringMessage( 'blacklisted: ' + doc.domain );
+    }
+    */
+
     is_usable = is_html &&
         location &&
-        location.protocol !== 'about:' &&
-        location.protocol !== 'chrome:';
+        location.protocol !== 'about:'  &&
+        location.protocol !== 'chrome:' &&
+        !domain_is_blacklisted;
     try {
         is_my_readme = location && location.href == itsalltext.README;
         /*
diff --git a/src/chrome/content/preferences.xul b/src/chrome/content/preferences.xul
index cebe000..444a3a2 100644
--- a/src/chrome/content/preferences.xul
+++ b/src/chrome/content/preferences.xul
@@ -34,6 +34,8 @@
                   name="extensions.itsalltext.fade_time" type="string" />
       <preference id="pref_hotkey"
                   name="extensions.itsalltext.hotkey" type="string" />
+      <preference id="pref_blacklist_domains"
+                  name="extensions.itsalltext.blacklist_domains" type="string" />
       <preference id="pref_debug"
                   name="extensions.itsalltext.debug" type="bool" />
     </preferences>
@@ -124,6 +126,12 @@
               <spacer />
             </hbox>
           </row>
+          <row align="baseline">
+            <label control="blacklist_domains"
+                   value="&blacklist_domains.label;" />
+            <textbox preference="pref_blacklist_domains" id="blacklist_domains"
+                    size="30" tabindex="12" multiline="true"/>
+          </row>
         </rows>
       </grid>
       <vbox id="help" flex="1">
diff --git a/src/chrome/locale/en-US/preferences.dtd b/src/chrome/locale/en-US/preferences.dtd
index 7b7ab24..829f42c 100644
--- a/src/chrome/locale/en-US/preferences.dtd
+++ b/src/chrome/locale/en-US/preferences.dtd
@@ -14,3 +14,4 @@
 <!ENTITY gumdrop_position.lower_left "Lower Left">
 <!ENTITY gumdrop_position.lower_right "Lower Right">
 <!ENTITY fade_time.label "Duration of button fade">
+<!ENTITY blacklist_domains.label "Domains to blacklist (accepts RegExp; one per line)">