I have a paper that was accepted for publication and we the authors have already filled out the copyright transfer. There was a disclaimer saying we're not allowed to share the paper publicy before 2 years.
However, I received an email by a PhD student saying his institution doesn't have access to the journal and that he'd like a copy.
So... Is sending a copy of the paper to a single person ok? Or does it already count as "sharing online" and therefore is illegal?
Take home:
Generally speaking, you can share any version of your article with individuals via private communications (e.g., email).
If you want to be sure and/or you'd like to share in other ways/places, you should check the publisher website/the author guidelines for the specific journal/the form you signed for information about how, when, and where you can share various versions of the article in question.
Most publishers and journals have guidelines posted for how/when/where you can share various versions of a paper submitted for publication. It's important to note that the preprint/author's original manuscript, the accepted manuscript (including any edits from the review process), and the (final, formatted) published journal article all typically have different restrictions.
As far as I'm aware, nearly all academic journals allow authors to share even the final published journal article with individuals via private communications (e.g., email). The key here is that you aren't posting it somewhere that anyone can download it anytime.
As far as preprints and accepted manuscripts go, there are usually even looser restrictions on sharing. For example:
This is Elsevier's website showing their article sharing policies, including preprints, accepted manuscripts, and published journal articles. However, they note that sharing policies may vary in some of their journals, so if the journal you submitted to is published by Elsevier, you should check the author guidelines for that journal.
A similar website for Taylor & Francis also shows that you're allowed to share both the preprint and the accepted manuscript, but it also has some suggestions for using a Creative Commons license if you plan to post the accepted manuscript online.
Other Notes:
You seem to have discovered that you have a specific license to do this, so all is well. Most authors will get such a license whin they give up copyright. In the absence of that it isn't permitted.
There was a time when an author got a quite large number of "offprints" of their article specifically intended for limited sharing. I vaguely remember about 100 printed copies from an article in an ACM journal.
However: Such "very small scale sharing" is widely done, and unlikely to be objected to if you do it in a very limited way. In particular, sharing within a working group is "considered" fine.
While it might be, for some, a technical violation you can lessen the likelihood of any complaint by sharing a physical copy only, not a pdf or other electronic version, with instructions to not pass it on,
and,
sharing an older version rather than the one formatted for publication. The version you originally submitted would likely be "ok". Caveat: User Greg Martin points out, correctly, in a comment that sharing older versions need to contain correct results and will, in any case, complicate citations. But note that some publishers are sensitive about final, formatted, versions.
Note that, while it is, in some cases, a violation, it will likely be ignored. It might not be ignored if done by someone else, but author relations are considered.
Don't consider the above to be legal advice, but just a description of how the world works in practice. One of the main reasons for copyright is to protect financial interests. But they are so small here that "the law does not concern itself with trifles" is likely to apply.
