This is not a battle the RIAA can win. As soon as they took down Suprnova, traffic for all the other torrent sites would have increased. Every time they shut down something, something else will open. And they don't have any jurisdiction in many countries, such as China, so can't touch many of the sites.
And even if they did manage to sweep the http internet clear of piracy, the piracy on IRC and other places would increase to match the demand for pirate copies.
The RIAA can't win against this sort of piracy, it's more like a tax placed on all movies and games and will never disappear unless they place every aspect of computing under one central authority (ie. Microsoft TCPA, shudder). Then every user will suffer.
But, they can do more against the mass reproduction of pirated DVDs which is a multi-billion dollar industry. They'd just rather hit against an easier target.