Now you can do the banning you wish Google would do.

That works about as straightforwardly as you’d expect — once installed, you’ll simply see a link to block a site along with each search result, and you’ll also be able to unblock sites at any time if you go a bit overboard. What’s most interesting, however, is that Google says it’s going to study the feedback it gets from extension and that it will consider using it as a potential ranking signal for its search results.