http://www.cnn.com/2007/SHOWBIZ/06/2....ap/index.html
It would appear that, yes, pressuring ISPs and hosting companies is a very good way to get things shut down. Porn people need to learn from this situation, DMCA after DMCA does get something done, because big companies don't want to end up on the hook for the criminals. They have something to lose, the criminals mostly don't.