Very recently Google has announced the support for the cross domain canonical tag that basically allows webmasters to have the same content in more than one place and telling Google which one is the main version. The one that show up in their SERPS; your master copy so-to-speak.
This is pretty big.
Basically if you have a version of the article on your site (i.e.: www.yourwebsite/article.html) and the same version on an article directory (i.e.: www.articledirectory.com/article.html) to achieve more traffic you would take the latter article and add this statement in the head section of their page:
<link rel=â€canonical†href=â€http://www.yourwebsite.com/article.html†/>
Google did not mention if this link will pass PageRank but it probably does (even if a little bit) as publishing your article is still a strong endorsement.
Write, write, write 🙂