That is a question that has been asked several times here, and the answer is yes.
One thing you do need to understand is what the Uniquifier plugin actually does. It DOES NOT make the content UNIQUIE. What it does is when the php executes it uses garbage code to distort the content of the text.
I have tested this on a site before, however my tests where inconclusive of whether it actually works or not. That is to say, yes sure content passed copyscape. However I would find no real confirmation if content was passing G or not.
My gut feeling is that as I could still actually find my site on G with the plugin installed, it tells me that G was translating the garbage therefore it would be reasonable to asume that they was recognising the content as duplicate.
People need to remember that copyscape is in noway linked to G and therefore should only be used as a guide and not a definative answer!
Now if G bought out a new feature in the webmaster tools to allow websters to check for duplicate content (ie there own content protection feature to check if people are stealing your content) that would really kick ass and help alot!
I have done alot of soul searching and looking hard for a solution to automated blogging that will bring 100% uniquie content and have found nothing. Todate the best thing I have found is Content Spinning, which in itself is pretty cool.
Basically you take an article and mark up replacement text for the current text. Here is an example:
Code:
For the [tourist,visitor,traveler] [who,that] wants to see [it all,everything], [there is a,they can get on a] tour bus that travels [all around,the length and breadth of,a circuit around] the city.
Now you can see that if you read and pick out any word or phrase between the [] it will make readable sentances. As you can imagine it will take a little longer to write the articles. However, what this means is that using this in conjunction with the WP Sinner plugin, each time the page refreshes it will pick out 1 word or phrase from the [] and create the document. Therefore each time giving you a Uniquie article. This is great because G will think that it is always changing and upto date. Remember G only has a memory of the previous page it cached, therefore when you have a 500 word article the chance of getting the same combination twcie is a row is nearly 0%.
So now that you have taken the time to write this, you still only have 1 article on 1 page! So all you do is simply refresh the screen, copy the page and put it into a new post, and repeat and rinse, repeat and rinse. Before you know it from 1 article you can get 100 uniquie articles.
The more and more articles that you write like this, the quicker it will become to write them, as your brain will naturally get trained to using and knowing replacement/substitute words. My first article took me 3 hours, however my second took me 1 hour. But now I can write them within 20 mins. Not bad for potentially 100 uniquie articles!