Google's recently taken aim at content farms and other spam sites by letting Chrome users give feedback by making sites as spam. Now, users of other browsers have the same ability — almost.
Google searchers should find a new feature in their search results this morning. Now, whenever you click on a search result and then hit the "back" button to return to Google, you'll see a new link next to the "cache" button, that will let you block that domain from further searches. After your next search, you won't see them show up anymore, and your search results should be of slightly higher quality. Of course, you can always un-block a site by scrolling to the bottom of your search results and hitting the link to view your blocked sites.
However, unlike the Chrome extension, Google is not yet using the information about the sites you block. That means the sites you block don't contribute to any greater good, as they would with the Chrome extension — they just keep your search results a bit cleaner. Google is still collecting the info, they just aren't currently using to clean up their search resutls. So if you're a Chrome user, I'd keep the extension installed for now so you can still contribute to their Spring cleaning — but all other users should feel a bit better that now they can at least clean up their own results right from Google. Hit the link to read more.
Hide Sites to Find More of What You Want [Official Google Blog]