I've been using this for several years with Google Search, and it was initially very effective in blocking unwanted results. For some time now, it has failed to block "sponsored" results, which may be a drawback it can't overcome--and so I've become accustomed to ignoring the top handful. Today I discovered a new wrinkle. Sadly, some sites have evidently strong-armed Google into ignoring my wish never to be reminded of them, specifically Amazon and Goodreads, an Amazon subsidiary. This add-on has therefore become much less useful to me. I would be happy to support it financially if it were more robust.