Whether having copies of your articles around the web helps you is very dependant on the
seo abilities of each website publisher.
Personally, I have worked with another developer to create a product that creates unique pages/websites for each "copy" of the same article. Something is only duplicate if the keyphrase searched for has the same 150 snippet or words around it. So you can generally make the title of the article unique, but the content of the article if searched for specifically would be duplicate. See the following as an example of the
seo that is possible -
http://www.marketitonline.co.nz/articles/
How many people would go to that bother of getting such uniqueness?
How many people would give the site sufficient inbound links to get it the
PR needed for the outbound links to be any value to the publisher?
How many people would add rel=nofollow to all links on the article?
There are lots of unknowns out there.