I know ezinearticles is fussy about each article and checks for uniqueness but what about other sites? For example if you had a batch of fairly fresh but not unique PLR articles could you just go bang, bang and create a whole load of Squdoo lenses? Yes, unique is better but I don't think the Google duplicate filter is that big a deal. This approach would certainly be faster than trying to rewrite 20 articles several times each. So the question is do places like Sqidoo and Hubpages actually check for duplicate content before the article goes live? Perhaps just changing the title might be enough.
Think about it. If you go the trouble of writing a unique article for Ezinearticles and it is taken and used by a number of other sites then it becomes duplicate content anyway.
squidoo and hubpages put up content immediately, doesn't matter if it's duplicate or not. The only problem with duplicate content is it's a lot harder to rank for in google, because its already out there and on the net. But it's still good for backlinks, and getting traffic from squidoo searches and such.