It’s to the point that some people are almost obsessed with the issue and swear there are penalties associated with it. Google has 52,600 results for “duplicate content penalty” and WebmasterWorld has 6,160 threads discussing the subject.
So what happens when one article is hosted on many different sites? All the articles rank well if you have trusted domains according to Google. It seems illogical based on all the discussions but here’s a recent example I ran across.
At the end of January an article titled “Will ‘unlocked’ cellphones free consumers?” was published on CNet, ZDnet India, ZDnet Asia, and USA Today. Within days, all four versions where ranking in the top 30 results for unlocked cell phones.
There seems to be a disconnect between sites that Google indexes and sites that Google considers authorities. If Google considers your site an authority it seems you can get away with almost anything short of blatant spam (i.e. BMW example). I personally believe duplicate off site content can decrease the overall quality score of most sites thus affecting the overall ranking of these sites unless of course you have the Google golden ticket.
How does one go about getting a golden ticket? You could always try and bribe Matt Cutts. Short of that you need massive amounts of links. This is where I believe social media marketing comes into play. While you still need link ninjas to rank for specific terms, you now need link pirates to go out there and plunder the social media landscape for thousands upon thousands of links.