Add the ability to permanently leave specific websites out of search results

In this day and age the web is becoming less and less useful as a research tool due to the very high number of duplicated content (usually rubbish to boot, simply to promote google ads), as well as websites that list as a free item what you were searching for, but then is not free at all.

I would be a huge user of a feature to add websites to a list that they may never appear in search results (black listed).