Interesting to see their approach and the reasons why they are not building more features on top of ArXiv. Although comments on papers might be a dangerous area to venture into there are definitely places on the web where the ability to annotate and comment papers is helping science move forward. A good example is the Polymath project and Terry Tao&#x27;s blog. Tao&#x27;s recent solution to the Erdos discrepancy problem,an 80-year-old number theory problem, was actually triggered by a comment on his blog. Another example is www.fermatslibrary.com. Although the papers in the platform are more historical&#x2F;foundational, they were able to get consistently good&#x2F;constructive comments that help people understand papers better.