I'm one of the engineers here at Abine, creators of DoNotTrackPlus. Someone gave us the link to this forum post in their feedback and I wanted to shed some light on this issue.
We fight trackers by both blocking them and opting you out of being tracked. There are 2 different methods, and you can learn about them here: http://www.donottrackplus.com/whatisoptout.php
There are both good and bad cookies, and we add the good kind to your browser. They’re called “opt-out cookies,” and they signal to advertisers that you want to opt-out of receiving target advertising (it's like the "Do Not Call" list for targeted advertising). But while regular cookies tell Web sites information about your online behavior, opt-out cookies tell advertising companies that you *don't want* to receive targeted advertising. They're the same cookies for everybody, so they can't be used to track you, and we keep them from getting deleted to ensure maximum opt-outs.
You can read more about the NAI, the advertising industry initiative to let people opt-out, here: http://www.networkadvertising.org/managing/opt_out.asp
If we can answer any other questions, please contact us anytime at support [at] getabine.com !