Back in the day, and I do not mean all that long ago, I used to plaster duplicate content across several domains and I took over at least 60% of page one in all of the major search engines. This went on for about 1 year before they pulled 5 of the 6 sites down for that content. Don't get me wrong, they didn't de-list the sites as the sites themselves still ranked for their main keywords. Rather they started ranking only one site for all of that duplicate content.

While it is harder these days to pull these types of stunts off I am here to tell you that it can still be done. Hell all you really have to look at are organizations that offer white label products to see this sort of thing still happening. Personally I do not use any cloaking tricks or any of that other stuff but I would imagine that if one were to use them one would have even more luck.

Regarding ethics... only you can decide if your tactics are ethical - just don't try to force your ethics on me while making your choices.

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You can lead a blonde to reason but you can't make her think!