This is all very old ways of thinking, ideally its best to focus on creating valuable data as you see fit. What are your users looking for? Can this help the user? Is this interesting to the user.
1) Yes if the article is relevant and helps the user
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Yes if the article is relevant and helps the user
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First off I am not a fan of article sites. They have adds on them and Google already cracked down on this cheap strategy. It can be done but I don't recommend it. You are better off having the content on your own site and get people/other bloggers to link to it.
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One unique article should go one one unique site and only reference (Link to or from) authoritative sites.
Hope this helps.