Mutable is a free browser extension that allows you to control unwanted content across the web. Mutable's powerful parser will ensure that any posts or content containing terms or phrases you select are blurred, hidden, or replaced with cute pics of animals.
I would love it if you could do sentiment analysis of headlines and just hide everything that's above, say, a certain negativity threshold. I love the concept but find it difficult to predict keywords that I want to hide.