Is it illegal to share publications not in the public domain with collaborators? Back in my university days, I got into the habit of saving papers I had to read to my hard disk. At first I did this simply to organize them more conveniently, and have quicker access to them. 

However, my reasons for saving those papers to disk gradually changed as graduation approached. In the end, I saved a lot of papers, because at one point I realized that I had unrestricted, unlimited, free access to an absolutely fantastic source of richness, and that soon after graduation, I'd lose all of that.  

Years later, I now frequently end up in discussions, or get asked questions, or otherwise end up at a point where a common access to one of those papers really helps to progress the discussion. I often just send that paper around without thinking twice about it, more because I believe that's how science should work than anything else. 

I believe most of those papers are however not in the public domain, meaning, people not associated with a university or other institution that has access, can not access the paper without some payment to its official publisher.

So is any of this legal? If not, what are the possible repercussions for me personally, and for the people I sent it to? 

I realize this is a touchy issue, and there are many initiatives to open scientific publications up for the general public. A related question would be: do these initiatives (like all of these) exist partly because of this reason?
So is any of this legal?


Unless your sharing falls under fair use in your particular country (and with the Internet, sharing online is a tricky business anyway), you should not share the papers.

If you want to share the papers, linking to the original source is the best option, and Google Scholar or other online repositories can get you pretty far with a lot of material.  If you can't find an online source, you are limited to providing a cite and hope that whoever wants to find the article can use their library to source it.


  If not, what are the possible repercussions for me personally, and for the people I sent it to?


Practically?  Unless you are sharing the files openly to a broad audience (i.e., so they are available online), no one is going to track you down to sue you.  I would avoid linking directly to articles that aren't behind a paywall, but emailing them to people you are collaborating with is unlikely to cause you any trouble.