I understand this question is asked frequently but my case is slightly different.
I work for a website allowing users to have their own blogs and it might happen that one of the authors might decide to leave my website to self-host his blog.
I want to take a friendly approach when this happens, that is, I will help the blogger in the export/import of data.
But what about duplicate content issues? If the blogger published 100 articles on my website, 100 links will be duplicated on two domains, mine and his:
How shall I tackle this problem? I mean both URLs will have the same, exact content and that is because I will not remove the articles from my website.
Will I be penalized by Google because of duplicate content?