The free Espacenet patent database contains a vast number of patents and can be searched in a number of ways. One of its features is the ability to create lists of important patents.
When a search is run, each entry in the results has a blue star on the left hand side. By clicking on the star, it turns red and the same entry is available in the "My patents list" folder above the hit list.
This means that useful patents can be noted for future study. In addition, if another search is run, those already marked in this way appear with a red rather than a blue star to show that they have already been put in the folder.
This is a useful feature and avoids wasted time looking at the same patents again and again in modified searches. Two small suggestions are that it would be useful if additional folders were available, and if they could be named, as a searcher might be dealing with more than one search.
However, this post is really about supplementing this concept of a folder of "positive", wanted, hits with a second folder of unwanted hits -- a negative folder.
Just as you can indicate that you "like" a patent, you should be able to indicate you "dislike" a patent that might seem from the brief details on the hit list to be relevant. In the same way as with the "likes", the searcher can simply disregard the entry on a revised search. There is no need to look at it again, you are reminded that you have already seen it and found it to be irrelevant.
Maybe the red star could be replaced by a "thumbs up" for positive and "thumbs down" for negative documents.