I noticed that Google just implemented a cool effect. When you search for anything and click on a site from its result list, and then if you click on the "back" button to go back to the result list, you will notice that there is a new "Block all results from <this url>" link showing underneath that result column. The really cool thing about this is the shimmering effect that runs only once, so it catches your attention without distracting you too much afterward.

I was inspecting its element, and I notice that google is using an image called "shimmer_mask.png" to do its trick. And I wonder if anyone knows how to implement it?