There have been a rash of plugins developed lately that offer the ability to make content "unique". Some of these plugins are here on the WF and several have probably landed in your inbox as well (emails from your favorite guru). I'm not going to name names or post links to the plugins I'm talking about because I don't want to break any forum rules.
Most of these plugins make the content "unique" by:
1. Changing the way the search engines view the content by altering code
2. Spinning the content so that it "reads" differently
Can these plugins be used ethically and legally...most likely but I feel a warning is still in order just to be sure that those who don't know (newbies) are at least informed of what NOT to do and how NOT to use them...
Trying to trick the search engines has never been a good idea and most that have done it have learned the hard way eventually. Google and the others will eventually learn about these new tricks and if you are using these types of tactics it could lead to big trouble like your sites being banned, Adsense accounts being shut down...etc
Spinning content that is scraped from outside sources (such as article directories) will most likely break the TOS of those sources (not to mention it's most likely illegal). If the plugin is designed to allow you to not only change the wording of the article but strip out the links as well then you are certainly flirting with trouble. If you're caught doing these kinds of things you not only have to worry about the problems listed above but legal issues as well.
As I said, some of these plugins CAN be used legally and ethically (on your own content and PLR) but as we all know...not everyone will do this. Just be sure if you are using plugins with these capabilities that you are playing by the rules. I'm not saying that using these plugins WILL result in losing your sites or different accounts but why take the chance?
Are a few extra bucks really worth all the trouble, damage to your reputation and possible legal issues? I don't think so.
Good luck with your IM