[jowsie]

The issue with this is the authors of some papers either don't respond or simply aren't alive anymore.

[daotoad]

It also scales really badly.

If a paper becomes prominent and many people want to read it, is it reasonable for the authors to be inundated with hundreds of requests for a copy?

What is the point of journals if we rely on word of mouth interactions to share information?

[pradn]

In the humanities, authors often upload to Academia.EDU. It doesn't seem to have as much use among scientists.