Official Google Blog: “Now there’s yet another way to find more of what you want on Google by blocking the sites you don’t want to see. You’ve probably had the experience where you’ve clicked a result and it wasn’t quite what you were looking for. Many times you’ll head right back to Google. Perhaps the result just wasn’t quite right, but sometimes you may dislike the site in general, whether it’s offensive…or of generally low quality. For times like these, you’ll start seeing a new option to block particular domains from your future search results. Now when you click a result and then return to Google, you’ll find a new link next to “Cached” that reads “Block all example.com results.” Once you click the link to “Block all example.com results” you’ll get a confirmation message, as well as the option to undo your choice. You’ll see the link whether or not you’re signed in, but the domains you block are connected with your Google Account, so you’ll need to sign in before you can confirm a block. Once you’ve blocked a domain, you won’t see it in your future search results.”