I have heard many stories from people who had their sites integrated elsewhere so that the visitors to those other sites would see the original one not even knowing that the sit
I guess the only solution is to maintain an ever changing website, to which users come to see the new content and interact with it in such a way that comments fuel new content. Then going to a mirrored vesion will be seen as an inconvenience to both users and authors. Of course, this wouldn't prevent mirroring, but only makes it less worthwhile, hopefully.