Imagine having a roommate who doesn't remember you want to avoid sugar and are allergic to nuts, yet keeps making PBJ sandwiches when it's his turn to make dinner. That and you're getting effin PBJ for dinner.
Web search: Don't show me anything from this domain again.
Google: You are so keen to remember things about me that I don't want you to remember. But you don't bother to remember what I reject? Of course, because I am the product, not the customer. This feature might run afoul of your relationship with advertisers, yeah?
Yelp search: You've suggested this place before, I spent the time to read the details and reviews and rejected it, but you keep showing it to me on future searches, and because as a human I can't remember all the stuff you've showed me before, I waste time considering it all over again. You even show me places I rated 1 star. STOP!
Maybe DuckDuckGo could add this feature? Please? Pretty Please?