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Recently had the same issue and we went with not indexing them. Two issues mainly - the duplicate content issue (same results being attributed to author, posts, categories etc - which i don't believe is too much of a problem. The other one though was the general titles being attribute to the results were pretty average. We tested both indexing of and excluding and didnt see any increase in traffic with them, so went with the exclude option. Hope it helps. Good luck.

I like the rel author option in this case.  It doesnt really take care of the indexing issues, but I lean toward not worrying about it.  In some cases, i let Google figure out which one they want to index given the two.  They will probably choose the original posting, but if you get comments and discussion, I can see that bubbling to the top.  Its more like news sites or aggregators at that point.

You won't lose PR. This is something that is most likely filtered out by search engines after a crawl. SEOmoz has probably just chosen not to implement such a filter.