What if I submit a same preprint to several open access repositories, e.g. arxiv, vixra, philica etc.?
I guess doing so would give to a paper more visibility. But would it be a bad practice? Would it be unethical? Scientific community would complain or blacklist me? Is there any copyright issues, or other notes that I should know? What do you advice?
I know it's unethical to submit a paper to more than a journal (or maybe conferences), but here I want to know about preprints and open repositories.
In addition to the great answers by hnltraveler and user102 on the moral aspects of the question let me add some more technical points:
Duplicates in scholar search services
If you are searching for publications with Google Schoolar or similar you will find that these systems already aggregate multiple sources for the same publication.
So you wont confuse your audience with multiple identical versions (just be sure to update all of them if you change something).
Preprint services let you choose the license of your work (for example Creative Commons) and with many of these even other people could re-upload your work onto other services. As long as you hold the copyright to your work (or remain the right to publish a preprint version) you can upload your paper to as many repositories as you like.
Some preprint services like Zenodo allow you to set a relation to another source (via Identifier like DOI): Zenodo Example*
You can also add multiple references to the same work in your ORCID profile: ORCID Example*
- References to my own work as I didn't find other examples really quickly enough.