Thanks for the links! I am not sure how well Xor Filters would fit here because they're meant to be immutable, whereas the extension has a content script that a

Thanks for the links! I am not sure how well Xor Filters would fit here because they're meant to be immutable, whereas the extension has a content script that adds any submissions from /new or the front page to the Bloom filter so you can navigate directly back to the discussion. I had not heard of PinSketches before this, and will definitely look into them. As I mentioned in another comment: the way the project is set up, it should be possible to do a drop-in replacement with a better data structure, should one come along. Thanks!