What could be built on top of a World Digital Math Library? | chorasimilarity

"The title is copy-pasted from the following question by Ingrid Daubechies, on mathforge.org [I added some links]: 'Suppose most mathematical research papers were freely accessible online. Suppose a well-organized platform existed where responsible users could write comments on any paper (linking to its doi, Arxiv number, or other electronic identifier from which it could be retrieved freely), or even 'mark it up' (pointing to similar arguments elsewhere, catch and correct mistakes, e.g.), and where you could see others’ comments and mark-ups. Would this be, or evolve into, a useful tool for mathematical research? What features would be necessary, useful, or to-be-avoided-at-all-costs? This is not a rhetorical question: a committee of the National Research Council is looking into what could be built on top of a World Digital Math Library, to make it even more useful to the mathematical community than having all the materials available. This study is being funded by the Sloan Foundation. Input from the mathematical community would be very useful.