https://addons.mozilla.org/en-US/firefox/addon/stumbleupon/
YouTube Comment Snob Update: YouTube Comment Snob for Chrome is now known as “Comment Snob,” and it works on many more websites. YouTube Comment Snob is an extension for Firefox that filters out undesirable comments from YouTube comment threads. You can choose to have any of the following rules mark a comment for removal: QuickDrag SmoothWheel FacebookGamer Pearltrees