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Just relating what I recently saw on social media: apparently, there are Standford students who created a sort of wrapper around arXiv (https://alphaxiv.org/), through which everyone can comment on arXiv papers
Not sure if this is effectively useful for every paper, but feedback is always valuable so I thought I would share this info here
They have a short demo video on X https://x.com/i/status/1818669016325800216
I hope they have a good moderation plan!
Something like this was tried a decade ago as the Selected Papers Network. Maybe this one will be more successful.
There's also https://scirate.com, which has been in use for many years now, mainly by quantum information theorists. It has the additional feature/bug that papers can be voted on ('scited').
All the featured papers seem to be about machine learning / large language models. That makes sense if they're trying to get buy-in.