Originally Posted by Linkster

The problem is that the results are (at least the ones I looked at) tagged with the supplemental page tag in Google and that is a dampening factor that affects not just those pages but the site as a whole. If someone likes their SE results to be a source of traffic, its not a good idea to add duped pages. But like you say if they have no desire to rank in Google, and have a good source of traffic it does look good for that case