Actually, not anymore. Scientific publications, at least in the West, are increasingly stipulating that they have complete, EXCLUSIVE rights over the paper (even though the researcher pays THEM to publish it). That would mean that as soon as they sign the contract to publish, the researchers themselves distributing that paper is illegal. It's total bullshit.
If a real human emailed me about a paper I have on the arXiv I would probably be thrilled even if it was just dumb trolling.
i dont get it
Arxiv is a web archive where authors can publish their scientific papers, usually preprint.
The joke is you usually hear : "email the author to get the paper" but arxiv is not like a journal: it has already the PDF freely available.