> Kind of the opposite, sci-hub isn't really curated at all. Its goal is to have a PDF for everything that has a DOI, more or less.

Side-stepping the politics and legality for a moment, I find it interesting how this is a very natural example of the fault-tolerant design of networks.

A 'DOI' is a resource locator. There's a 'fault' in the network in that some people cannot locate the resource when providing the DOI. Sci-hub has sprung up to route around this fault, and provide people with the resource.

Practically, there are real people making decisions who are involved in this process, but on an abstract level it feels like this is somehow inevitable? It feels like an emergent behavior from any sufficiently advanced network, and any attempt to stop it seems futile.

I guess another important part is that it's the universities' connection that scihub 'uploaders' tunnel through that are key - they have the special network access to DOI resources that make it free for on-site university users to get anything for free, and then the 'uploaders' relay them to outsiders. That's a difference between papers and something like 'scihub for any pdf ebook via ISBN' - there's no special network that can get all ebooks for free just via ISBN - except maybe the Library of Congress ;)

> I guess another important part is that it's the universities' connection that scihub 'uploaders' tunnel through that are key

Does this happen in realtime? I read that sci-hub sometimes uses credentials from legitimate users, but in that case they would be easily identified.

So, perhaps someone with access submits papers on request? And if so, what about watermarking?

> And if so, what about watermarking?

years ago i recommended to scihub that they should use https://github.com/kanzure/pdfparanoia but they weren't too concerned.

Plenty of the papers I've gotten from scihub are watermarked. The "downloaded by [IP] at [timestamp]" footer could probably be stripped, but they don't appear to do so, or at least not consistently.